All you seem to have done is provided a receipt for his deposit. What he did is put down $200 to keep the option to buy the car open. Unless you told him that the deposit is non-refundable he is entitled to that money back. Same thing if you went to a dealer to buy a car and put down a deposit on car. Unless they specify that the deposit is non-refundable like in the case of special cars, you have the right to get your money back. I don't know what these other people are thinking.