I looked at your post again. Here is what I would have done differently.

If I was unable to get the car ready as promised i would have called him and said I need a few more days to make the repairs. I'd not have agreed to pay a tow for him. If that was insufficient to satisfy him I might at that time have agreed to refund half the money but probably not all.

Nobody is perfect, not even a dealer.

In a situation like this requesting a few more days is not unreasonable.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.