To the courts.  You have to have someone read all the documentation on your behalf in order to determine what the rights and liabilities of the parties are here.  And you need to get something in writing from the risk department as to why they are not honoring the claim.  I am assuming that the company that did this was licensed and bonded and they committed negligence in what they did.  They should be insured for it.  It may be a good idea for you to pay an attorney on a consultation basis only for the matter and to write a letter on your behalf.  If this does not work at least you will have a good outline on what you need to do to sue the company.  Good luck.