If enough time has elapsed (I think it's 4 days) file a non-paying bidder dispute (Go to My Ebay->account->resolution center) and after a week if the deadbeat hasn't paid, you can close out the case (Don't forget to do that!) and you will get a credit for your fee.
Motors deals are "non-binding" only in the sense that Ebay can't force a bidder to pay, or a seller to sell.....but bidders still get a non-paying bidder strike, and sellers who refuse to sell still get a non-performing seller strike.
In the future, I would recommend listing any vehicle only as a fixed-price listing, with "immediate deposit required" [check the little box on the listing form) so that recreational bidders can't end your ad- they'll have to pay the deposit in order to end the listing.
