I've gone through this with both of my big resto's. You just need to roll with it. My coupe was promised at the end of April, 2013. We picked it up the week before Thanksgiving.

I just kept showing up at the shop a few times a month "to document" progress for my photo album. I think that helped. I never got mad, yelled, etc. It seems all shops operate in this manner. I know it's hard to deal with, but eventually they get done, and I think they do a better job than if you bich and moan all along the way. Plus I still have a good relationship with them in case I need some touchup or small additional thing done.

And in my case, I had another 'bird to drive during this process, so I'll admit it was a bit easier. These cars are done almost at cost, so they need to fit them in wherever they can whenever they can.

Hope you can stick with them. You may need their help later.