Rookie Mistake...
The problem is they take on work when they are behind with other work that has already been paid for, then a new sucker comes in with cash and your project gets put on the back burner. I guarantee there are others with your same problem no matter how many projects they have coming in. I have seen over 50 projects come and go in the last 13 years mine has been sitting. He has an off-site storage place where my car sits, I haven't even seen it in 6 years though some of the parts are still sitting around his shop...