Rookie Mistake...

I agree with the majority. Go unannounced and ready with truck trailer to get your car and all belonging to you. Having the police there is also good advice. It unfortunate that this is happening to you and the big thing we cannot recoup is time lost. When you finally find another shop to do what should have been done you certainly won't fall into the same trap. Sorry you have to go through this but I wish you smooth sailing from here on.