My identity was stolen. Reported. Still being sent to collections.

I don’t know what else to do and would like some help. 

Several months ago someone stole my identity and used it to open an Xfinity account in another state (I am a customer). I only found out when it showed up on my credit report. I worked with that collections company to get it removed from my report and submitted all of the paperwork to Xfinity. This was back on March. 

I now have a new collection agency calling me for the same fraud amount. I keep trying to call Xfinity and give them my case number. Half the time the customer service agent cannot help me because they are looking at my actual account and it’s paid in full. When I do talk to someone in the right department, I have been told not to worry because the collection will be removed from my credit report. Well the new collection company just sent it to the credit agencies again and now I have to start the process all over again to have it removed. I am beyond frustrated. Is there anyone at Xfinity that can actually resolve this and go to the new  collection agency and remove the ding on my credit report and resolve this once and for all?