Also try the better buisness bureau. Never had a mount done but i assume they need a license for it. It may be why he moved to begin with. he had to many complaints.
talk to a lawyer, see what they have to say. You may be intitled to what you payed plus any losses. go after him. If you don't want to go that far then you might as well just let it be and chalk it up to a loss.
It's up to you now to make up your mind how far you want to take this in order to get refunded on money and losses. Odds are he does not even have that rack anymore.