Almost all engine builders take way longer than they tell you.
Too late, but my advise would be get it in writting. Always have a signed list of parts you take to a builder, an estimate of what's to be done and a esimate of the cost.
If he didn't take anything from you (I mean steal something) their is very little you can do. If there is no intent of fraud, which in this case would be next to impossible to prove partly because you took the parts to him and he has done (and still working on them). You can get the police involved, but there is not much they will do. They may even threaten him, but again they only have your word against his. I was involved in this same kind of situation that lasted almost a year.
There were many phone calls to the police, many to the builder and the owner of the motor unfortunate for me I was just the middle man that took the parts to the builder. The owner of motor told the builder he wasn't in a hurry and didn't plan to race for almost a year, but after a few months got impatient. I learned a good leason from that one. Get everything in writting and everybody will be on the same page and you will have proof if it does have to become a legal matter.