I certainly can't coment on all that has been written about this subject, becaues it sounds like only you and he really know what happened. I will say this; If you are not a turbine certified pilot and he did not throughly invistigate this, you should have someone write to the AMA and have his turbine waiver suspended. That is the type of stuff everyone is now paying a lot of attention to.

Depending on how recent the action was taken, you may have the right of appeal. Act quickly though the time limit is usually about 30 days. If you don't pay he can hire a lawyer, and pay him to collect. Not sure where you are in the finanacial world, but how you deal with paying a debt is your decision.