Blackmailed by an exam taking service

I am currently being blackmailed some time after using the exam takers service. They threatened to report me to my university and employer immediately if I did not send them an obscene amount of money that only the wealthy would have on hand. What can I do to stop them?

I definitely wouldn't do what the last few blackmail victims have done. They posted endless details here about their exchanges, including screen shots of documents. In my opinion, you should simply name company here for the benefit of other potential victims and then completely ignore all future communications from that company. Block them on every medium through which they've contacted you and if anything from them still manages to get through, simply delete it, unread. They will stop bothering you much sooner if you don't respond at all than they will if you engage them in any kind of communication about it.

Would it be in my best interest to notify my university of the black mail?

Absolutely not. That's like shooting yourself first because someone is threatening to shoot you. Chances are it's a bluff, because there's no such thing as any essay company that sometimes provides real essays (or tests) and only sometimes blackmails their clients: Apparently, blackmail is their "business model." They probably do this to all of their clients and they probably just forget about those who ignore them. Once you respond, they have you on their hook and they'll start trying to reel you in. They'll also know that they have you worried. I don't know why victims are always so reluctant to take this advice here and/or why they always insist on continuing to post about it more; but that's a mistake. Name the company for the benefit of other potential victims and then block them from contacting you by any means. Don't even think about contacting your school "pre-emptively."

@Unknown12335

There is recent advice to other people who are in the same position as yourself.
In particular @noted has provided extensive, sound advice.

If it gets to the stage where you receive a likely 'fake' Department for Education (dfe) letter, then post it on here, as you can't be identified from it. The main purpose of publishing a fake letter is that it identifies the scammer including their address, which is likely fake too. As I am British, I am best placed to advise you about any letter purportedly from the dfe and confirm it is fake.

Meanwhile block and ignore the scamming company. Do not approach your university at this stage. You need only react to any contact your university may make towards you.

These people are preying on your fear of being discovered so close to the end of the academic year. They are entering the dry writing season and will not have enough work to spread out to their writers. They also will not be making much income from the students during the vacation period. They are going through their full roster of previous clients who have received the same email that you have. Their plan is to scare enough students to pay them for their silence, they are willing to negotiate the cost with you if you ask them nicely, do not do that. They are the ones scared right now. They are scared that they will not be able to scare enough previous clients into paying them. Do not be a victim of your own fear. Just keep quiet, ignore them, do not communicate with them, talk to no one. Do not even tell your best friend this has happened to you. It will blow over on its own. You do not have to do a thing. You do not have to be afraid of any consequences because there will not be any for you.