I had three days of intermittent TV and Internet service last month.
After my service stabilized, I made a fourth call to have my bill adjusted. Again, I got an outsourced call center rather than a Comcast-staffed call center. After repeating several times that I expected credit for all three days, the agent offered credit for first two, and finally three days.
I probably spent close to an hour, total, navigating the IVR system, on hold, and actually speaking to an agent over the course of the four calls. In the end, though, my bill (pre taxes/fees) was roughly 10% off, exactly where it ought to have been with a three day credit.
Got my next bill with no adjustment after the outage. Called for the fourth time and was told there would be a $14.XX adjustment. This appears to be a common problem with Comcast. When I turned in my "free" SD DTA, I never got an adjustment until I called again after being promised there would be an adjustment at the counter after waiting for over a half hour in line. My son had the same problem that lasted for over 6 months (he didn't bother to call) when he turned in the "free" DTA's. Comcast just doesn't appear to follow through on equipment or lack of service adjustments unless it's in their favor. I still find it distressing that when there are widespread outages, Comcast outsources their customer service. I guess this is there "customer service guarantee", what ever that means.