I switched up with Comcast in August 2009, so I have internet, cable and now phone with them.  Lets just say, it's taken them 6 separate visits to get my phone line right.  That's because they couldn't seem to grasp the concept that I had an Alarm System in my house, and the Alarm Company wasn't receiving any signal that my system was working.  They seemed to have finally gotten it right, but I truly don't have much confidence in them.