What a tard
Does he think its friggin walmart or something?
I got an idea, if this guy thinks he can just go and do things as he pleases, then tell him you'll take the chevelle back, but only give him back half of his money. Then sell him the 53 for that higher price.
If he wants to return it to you that bad, you might as well get a few bucks for having to deal with his sorry butt.