Pay back the money!!!!

I have sent assignments to be marked in January 2020. And have yet to receive my marks. After couple of months I phoned to ask what's going on, and after holding on for a while I got to speak to someone. I have finished paying them long ago. And it seems after that last payment they were just done. Now they want me to pay again to write exams. So that marks can also be kept somewhere.

I really at a lost. Is there a way to get your money back or something? I'm literally willing to pay a lawyer to take this people down. I believe they have f'd up a reasonable amount of people's futures.

Anyone that can help!