There is no 'next level'. This was a private sale, the OP didn't do anything like due diligence on the car, and they've bought an absolute snotter. Caveat emptor. There is no right of return, no reason for the seller to give any refund or even a partial refund. The contract is completed and appears to be completely legal.
If I was the seller, and received such a phone call, I would have to think very carefully about my reply. I mean, once I'd finished laughing of course.
Just because the guy you bought from gave you your money back, doesn't mean that he legally had to do so.