Paint mega-disaster (long rant)

You need to decide what you want at this point. I'm not usre what that may be: your car returned to you un-finished, your car painted, or ... ?

Remember that the money they want can buy about seven nice '65 Signets.

Unless you have a good original estimate or other documentation my opinion is that you should walk away from the shop and let them keep your car. I know it'll hurt because you've already sunk a lot into it but you'll find another car.