What do I do to get my money back because of poor owrkmanship?

You are entitled to have the work corrected at the contractor's expense. This means, generally, that you may hire a third-party contractor to correct the mistakes made and then sue to recover the reasonable charges of that third party. Note that you will likely either have to (a) actually pay for the repairs yourself before your can recover them from the "bad" contractor, or (b) hire an expert witness to prove the amount of your damages in court. In either case, you have no assurance of collecting the actual amount you have paid for repairs, and you will likely not be able to recover your own attorneys' fees for doing so. Moreover, the court will want a principled reason -- not merely your "feeling" -- for why you refused to allow the original contractor to correct his work.