It sounds exactly like what we saw, when they were updating the firmware, overnight in this area, to A28 for the new Guide. It still wasn't working in the early AM; I don't recall when exactly it was completed, sometime in the AM, though.
If it doesn't correct itself today, I would call for service in the evening, of course. There is no fee for this kind of problem, as it is Comcast's fault, not customer incompetence. Furthermore, his primary concern is getting the TV service working ASAP, not cost.