You should consult with an attorney immediately. Provide the attorney with a copy of the I-485 denial, the I-360 petition (and supporting documents) and the approval notice. Failure to file a response to the I-485 denial may result in the initiation of removal proceedings for the alleged sham marriage. This case is time sensitive and you should spare no expense in obtaining legal representation.
Please consult with and consider hiring an immigration attorney to represent you and protect your interests. Attorneys who practice immigration law are practicing federal law and therefore you can hire an attorney from anywhere in the country (as long as he/she is licensed).