My residential phone is registered on the "do not call" website but these dirtbags have called it repetedly today. No way to find out who is responsible but it is really intrusive. This is only one of many. I am beginning to think that Xfinity sells its customer numbers to what I call "vampire marketers". Cannot identify who keeps trying to fax and there is no way to make it stop. It amounts to cyberstalking. What creeps!