Quoted from Darkwing:Until the money changes hands, I don't see that anyone owes you anything. If you were driving to his house and the story changed when you got there, maybe then, but it sounds like he changed his mind or found a buyer for more money which is totally his right. You're out how much cash now? $0? That's right. Move on and find another machine. If you wanted it that badly you should have driven to his house ASAP instead of waiting for delivery or a meet part way.
You just summed up what's wrong in society right now. A man's word is worth nothing. Keep scolding the guy who thought he had the deal instead of the guy that broke his word. Great example.