Did they give you the parts back? If so have the flywheel checked by a (professional) verify that it is ok. Next did you sign an estimate for work to be done? If not there bill means nothing that is like work preformed without authorization you can get them on this, even if they say you gave it by phone, the only thing that hurts you is you paid the bill and probably signed the work order, all in all at least in NY DMV will make them refund part of the bill espescially if the flywheel is ok, and for the fact of no signed estimate to go ahead and repair. Good luck.