I have been getting these calls for about 10 days now, sometimes 2 or 3 times a day. One left the message that they were in the area and doing routine maintenance work and might have interruption in service.
I ended up calling the 800 number and they moved my phone number so hopefully I will not get these calls anylonger.
But I don't think this necessarily means your bill is late.
When the guy called and asked for my roommate, I asked him to hold because I wasn't sure if she was home or not. When I asked for a message, he quickly, almost inaudibly, said, "Yeah, cable company. Bye." So, it is, in fact, Comcast.