Who would favor in this situation? What should I do ?

I sold a car to a guy , told him that this vehicle is a manual . He says he know how to drive the car so after he pays me 1200 and I give him my car in perfect condition , that was oct 4 and the 18th comes around and he tells me that theres something wrong with the car .. I let him test drive the vehicle as well and have proof that he test drove the car and also that he brought the car AS IS. I later find out he cannot drive a manual and also have proof . He then proceeds to tell me that he want to keep the car and not pay the rest of what he owes on the vehicle. When I told him no I still need payment he says that he’ll just give it back and he wants his money back ? With damages already done to my vehicle and also registering my car with an illegal tag and driving it for 3 weeks ? And you don’t know how to drive a stick ? Mentioning also that the car is a 2003 Ford Mustang v6 with 200000+ miles with no check engine lights or damages when dropping the car off ?