FNB the worst bank

Good day I have this problem at hand. My girlfriend bought a Toyota Corolla from Godfrey Mahlo through our fnb account to his fnb bought as the money was transferred his account was blocked immediately by fnb and the person who blocked the account is DAVID MASHABA from fnb. It has been about 10 days today my girlfriend has been to the bank time and again the owner of the account Godfrey Mahlo has been to the bank with my girlfriend but yet David Mashaba from FNB doesn't want to open Godfrey Mahlo's account we even requested fnb to refund our money but they just don't want to reverse the money we have ask what is the problem they can't give us a reason for blocking the account we paid to