Well if you didn't use a middle man for that trade then theres nothing to do. As long as you have really good evidence, MPGH staff is able to ban. But if he has your money, there's nothing really to do. Next time use a middle man as in you give the middle man the money, you get the account. Then if all goes well, the middle man gives the money to the guy. If you need one for another trade talk to Some of the staff. Or I could help too.