Credit Mediators Inc Pursued payment on a fraudulent charge, filed a false report with TRW Upper Darby Pennsylvania

My credit card information was stolen and used to make a purchase. My credit card company informed the vendor of the fraud and refused to pay them, so the vendor hired CMI. I spoke with CMI almost on a daily basis for a couple of weeks and sent them the document from my credit card company attesting to the fraud. The agent told me that he understood I was not to blame for the charge, and that he had dug up some information on the person who had made the charge, but couldn't find the man. After speaking with the vendor, she told me she had instructed CMI to cease pursuing me for payment. She sent me a letter confirming that she had told CMI to stop pursuing me. The agent at CMI refused to issue me a similar letter when I asked him, even though the person who had hired them to collect the funds had told them to cease pursuing me.
Three months later I received a letter from CMI stating that they had filed a negative report with TRW over this issue. There is such a thing as the Fair Debt Collection Practices Act, but CMI does not behave as if this law applies to them. Does anyone know of a way to stop this company from destroying the credit of victims of fraud?

Ama
Landenberg, Pennsylvania
U.S.A.