I had a shop keep my block and head for four months. So I decided no more Mr Nice Guy, these guys were just jerking me around. I demanded my engine back and paid them for what they had done. Started over with another shop after getting clear with them about my expectations. It was an unfortunate, stressful, and costly experience all around, but I learned that many (not all) machine shops will only respect a customer who gets in their face and demands prompt service. Once they start putting you off and making excuses, don't cut them any slack, demand your work back and take it elsewhere. The longer it goes on, the less important your job is to them, because you let them get away with it once and they figure they have you by the short hairs.
If possible, avoid big shops with a lot of commercial accounts. Your work will sit while these jobs go out the door. You are much better off with a small Mom & Pop operation, where the machinist is also the shop manager and sales department. So at least if he turns out to be a lying swine, he can't point the finger at somebody else.
