Yeah, if they find something else that needs fixin', they have to call you and get your ok to do it. If you can get the truck back for $500 (plus sales tax?), do it. Otherwise, put it on a card and start the process with BBB, Consumer Protection Agency, Social Media, etc. You might even find a lawyer that will start a class action lawsuit. Don't take that crap without a fight, because they'll just keep doing "it" to others. "It" should always be consensual.