Sorry to hear that, situatons like this are frustrating for you the client and for the contractor. Many contracts have a binding arbitration clause that requires you arbitrate any disputes instead of the more expensive and lengthy court proceedings. I would check your contract for that and if it is there, that is a good avenue to go as each side presents it case in front of a neutral third party. If it is not in the contract than you can suggest it. There is also the less formal mediation process which is a good route if you think the relationship can be salvaged with some outside input.
If you need help or advice, please let me know. Thanks,