The usual way you regulate services is through regulation.

Criminal penalties for unauthorized raising of the dead, necromancy without a license, and existing related crimes like fraud, hiding a corpse, etc.

Regulatory penalties like license suspension/revocation for unfair, deceptive, and/or predatory business practices or failed inspections for adequate/safe facilities and rite materials.

There are private forms of limited regulation, too, like insurance coverage for malpractice or general liability.

People being imperfect, case law will quickly establish precedents, too.

The way you improve business behavior is usually through trade groups. Not the shady ones that merely lobby government, but the active ones that seek to educate members on best practices, provide forums for members to share problems, and promote research and improvement in the field.

Encourage competition, and make sure that antitrust laws are respected

Capitalism to the rescue!

It seems most problems you worry about are caused by necromancers either asking for outrageous fees, or deliberately performing subpar services to be able to demand fees more often.

However, if there is a healthy competition between them, they are forced to work for reasonable fees and provide adequate services, otherwise clients will go to competing necromancers.

This reminds me of shady car repair shops which deliberately do poor repairs so you will need them more often. If there are better and more honest repair shops in the area (and their reputation spreads), they will drive the shady ones out of business.

They're licensed practitioners, the easy way to deal with licensed practitioners who breach the terms of their license is to revoke said license.

The usual ombudsman service should suffice. There's no reason why what works for telecommunications and water supplies shouldn't work for necromancy services after all.

Perhaps they're also in need of a trade association, to assist them in showing that they're reputable practitioners and in setting reasonable prices for their services.

TL;DR: Make doing the job right interesting for the necromancers.

Raising undead isn't simple. It harnesses some magical power from very weird places on the other side of the Existential Plane, and thus has some interesting side-effects.

One of them is resultant of the prolonged contact of the once living mind with the now undead body. This is something the universe actively fights against, trying to correct itself and pull it back in the regular state of normality. This manifestation of the "will of the universe" happens in the forms of Deathberries, small, crystalline growths that grow inside the body of intelligent, fully restored undead - and only them. More so, stress and unhappiness seem to stunt the growth of these things, so you can't exactly farm them. You have to do it right - a proper restoration, followed by a proper maturation period.

For the normal populace, those berries are worthless. For the necromancers, however, they can be used to fuel all sorts of different magic, and even be used to simplify the creation of other undead. All in all, the berries are stored potential, waiting to be harnessed.

This creates a interesting situation for the necromancers.

They have to give maintenance to their undead clients every once in a while, so they may ask to harvest the Deathberries during the restoration ritual in exchange for a hefty discount on the prices. Since the berries only grow on "healthy undead", they have a very strong incentive to keep their clients satisfied and properly treated so they keep coming for more. The better job the necromancer does, more they will reap later on when their client comes back. The more time is allowed between the rituals, the more berries the necromancer can reap at once, thus making it less efficient to harvest them often.

Since you're presumably a leader of the conservative party, you can encourage the Necromancer Guild to regulate itself. Allow necromancers to create state by state Revival Bar Associations, allow the public to rate the necromancers on Yelp, and even allow newly revived subjects to rate their revival experience. The guilds will eventually publish good revival guidelines and tariffs can be placed on foreign H-1B zombies in order to encourage ethical young wizards to enter the necromancy marketplace.

I see a lot of purely business-oriented answers but none so far that tackle the environmental concerns so here goes

All You Need Is Kill

_{(not really, but the hyperbolic clickbait helps grab your attention)}

Dead bodies, including human ones, contribute to the natural cycle when they decompose. Thus, every zombie resurrected is a corpse snatched from and deprived the Earth. Deny the worms their food and you invite ecological collapse. Therefore we arrive at the principle we need to put into practice: for every pound of flesh in humans resurrected, an equal amount needs to be put back into the Earth

The first step is to measure and record the body weights of zombies raised. The administration and book keeping required would probably oblige the state to set up a Department of Graveland Security, or Department of Resurrection for a simpler title. Resurrection licenses and permits can also be handled by this new agency. Zombie control should be a lot easier than gun control if there isn't an influential lobby backing the necromancers.

Now for the tougher part, putting bodies into the ground. It's hard to do this domestically in a legal manner, although foreign soil is a very different matter. The best way to do so is probably through making use of the death sentence in states that retained it, and pushing for its reinstatement in states that didn't. Graveland Security will have to handle the logging of the inflow of human corpses, and ensuring the appropriate amount of them sit in the soil(no matter what their pesky families might say)

Now for the fun part, putting zombies in foreign territory. You can do so by enlisting necromancers and their zombies as private military contractors with the attendant regulations or lack thereof. Choose some failed state as your battlefield and let them loose. Encourage them to rack up as high a body count as possible through a similar incentive structure to those employed in regular armies. Here you can wring every last drop of plausible deniability as you can from them being PMCs and not formally part of the Army. Meanwhile body cameras on your zombies and follow up "accountancy" waves can help ensure you've reaped enough Third World flesh to fulfill your quota.

You can now terrorise countries for political purposes while throwing a bone to activists on both ends of the political spectrum. The horror and misery created should be perfect for Greenpeace sensationalism, while the alt-right gets to see their fantasy of Nazi zombies slaughtering the "untermensch". All worth it in the name of Mother Nature, of course

If you were a reasonable person who believed in a free and open market: nothing.

So what if some cut rate necromancer is charging an arm and a leg for their services?!? Don’t pay! The worst thing that happens is you die, and then your family (or better yet, estate) can hire a better, cheaper, and/or more reputable necromancer.

Those dodgey necromancers get shitty yelp reviews and the open market quickly deals with the problem. Sure, there will be some cut rate necromancers preying on the poor with no other options, but still better than being dead, right?

And of course, being the leader of the free world, you can offer the very best of services to those who sign up to a decade or two of completely voluntary military service!

• Control the resources used by the ritual itself.


• Register every individual that has been resurrected.


• Certification requires training.


• Resources are only acquirable by certified individuals with a strong cross-check on stock vs resurected.


• Enforce compulsory Warranties such as the resurrected must remain "alive", pass "psychological" examinations, and not have certain deterioration for at least x days - foregoing alternate reasons for failing such as a car crash.


• Criminalise certain practices such as raising mindless zombies, resurrection without a licence, carrying resurrection materials without authorisation.


• Fortify cemitaries, and morgues.


• Permit and establish support groups and unions for both the professionals, and the patients. This provides oversight, and a sense of community.


• Provide public system resurrection, with a set price. Permit private-system resurrections, they will have to be "better" to get clients.


• Require resurrections to be performed in front of other (frequently rotated) necromancers.

Just a few thoughts.

There exists many quality laws in the european union, like how much curving is allowed to a banana to be selled there. Why not making one for the undead.

§ 08/15 The undead goods

1. The necromancer has to guarantee the live of his undead for 3 months. If the undead is dying earlier the customer, gets another for free or the full price back.




2. If the undead is damaged due to customer actions the warranty expires.




3. If the undead doesn't fit with the description (skills, power, knowlegde) the customer can return him for the full price.



4. 
   

   The customer can always prolongue the contract, to the same price. No highering of the price is allowed.

   
   
   

   4.1. If the necromancer (business) sales the first month, it has to be
   especially stated, but isn't acknowledged as highering of the price.

   
   
   

   4.2. If the necromancer is losing more than 10% of the original contract income due to changings of the value of the currency, the necromancer has the right to readjust the price. The same right has the customer too.

   
   



5. If the necromancer (business) cannot provide the services anymore, the customer beomes the money refunded.

Hope this helps :)

The only answer is education. An informed public will be more resilient to scams. Additionally, you could open trade schools so that the power of necromancy is where it belongs, with the people. Raise up your people first. Then raise the dead.

Build a W.A.L.L.

And by WALL, you mean the Wights Animated to Legal Limbo task force. We all know illegal Aliens are entering the country via necromantic resurrection. Let WALL keep them in detention centers (conveniently, large buildings called “malls” exist from the last century. Just turn the “M” upside down) around the country in a tangle of legal states (only the unskilled ones from Mars though; Saturians and Jovians are fine). This is the perfect way to make good on two campaign promises at once (to kill two liberals with one tweet, as they say).

Impose tariffs on the nether realm

You need a trade war with the underworld. Place a tariff on the flow of souls to the other side; that will keep people from dying. Your distant relative, D. J. T. Cthulhu: Supreme Leader of the Underworld, will almost certainly retaliate with a tariff of their own on necromancers wishing to export souls.

Get the house majority leaders, cronenbergs Paul Pelosi and Nancy Ryan, on TV saying how good this will be for the economy.

Taking these steps will surely undermine the resurrection market, simultaneously ignoring the issue and making you look proactive.

Depends whether or not you want to be re-elected as president

The first solution that came to mind (not sure what that says about me) is to gather up a group of necromancers. Before they enter dress each one into exactly identical clothing and cover up every feature that tells them apart. Kill off about half of the necromancers and let the other halve resurrect them. Since they get resurrected with all their previous skills they should still be able to resurrect others. Kill off the other halve and repeat the process. The newly resurrected necromancers should have no other choice than to do exactly as their fine leader tells them.

If the legal system and economy is controlled by the far Right, then the Free Market will regulate the necromancers.

No one will pay for a half-assed job or one that doesn't last long enough, once they discover that the company they were thinking of using will not do what they advertise. I mean, wouldn't you check the company's Yelp rating before you get started? Every review comes from an honest customer (right?).

If you're unlucky (stupid) enough to be one of the first customers of a new company that doesn't do what they promised, you can always sue them. Since the legal system is also regulated by the Free Market, you will get the very best attorney you can afford. And so will the mega-corporation you're suing. All the judges will be the very best money can...I mean the best at legal stuff.

There will be no bias in the system because the Free Market fixes all ills. If you're dumb enough to pick a bad company, that's on you. Pick a better one next time a loved one dies.

This is the best answer and will fix everything. Or did you want an answer with suggestions that will actually work?

Ban Death

Take a wide scope approach and turn the raising of the dead into a commodity that is no longer competed for. Simply mandate that anyone who dies must be raised again immediately. The government can train huge numbers of people as necromancers and make it a public utility supported by tax dollars. All the perverse incentives of the free market are thus eliminated.