(800) 983-0950

It's Comcast making repeated dead calls (no one on the other end) to coerce you into calling them back. They were calling my cell phone about twice a day until I called back. To keep others from wasting extra time listening to options, press 3 to get their do not call list option, then enter your number once the system catches up and prompts you.
This is a bit of a disrespectful way to try to get business. Of course people are going to call and try to stop whoever is calling them with a dead line after enough time. If anyone complains about it they can just say "Well you're our customer and this time you called us, why is this our problem?"