"the cable has gone downhill from no sound to complete stops in the picture..."
Ahhhh yes, welcome to Comcast. I admit I'm biased, but with all my horrible experiences over the past 7-8 years with this company I feel justified in my "hate" - what some folks around here call a negative review, no?
Anyway, what you've described has been one of my ongoing Comcast battles. I honestly wish I could say otherwise, but that cable issue will not go away for you. Many, actually I think all, of my friends and colleagues have the exact same problem and none of us have been able to figure out how to get Comcast to fix it.
Unfortunately, they're the only viable game in town and they know it. They simply win by attrition, which is why I wish this industry as most would be forced to practice capitalism.