Fraudulent Xfinity Account. Ruined Credit Report

I am in the process of purchasing a house and when my mortgage broker pulled my credit we found a collections from Xfinity for $81 which dropped my credit significantly. After speaking with the collections agency and with Xfinity fraud we have confirmed this was a fraudulent account using my identity. I have spoken to Xfinity fraud help several times. They are telling me this process will take 30 - 90 days to resolve. Normally that would be ok, however I am closing on a house in 3 weeks and need immediate assistance. I need a letter explaining this is fraudulent so my mortgage broker can submit it to the credit bureau. The people on the phone have not been able to assist me with this. Is there anyway to make this happen? I have the ticket number that was created and the fraudulent account number associated with this issue. I am going to be without a place to live if this does not get resolved. Please assist me in anyway possible.