I have had a similar problem for a month. Bought a Bolt, switched my old cable card to the Bolt, worked fine except for 6 out of dozens of channels. While researching that issue, installed a new TV, only recieved 'standard' broadcast and some other channels (MeTV, ESPN3. CSPAN and some others (weird pattern), Had several techs out, no go. Comcast mailed me a new cable card; couldn't get it even recognized. Had tech out today, he had no cable cards despite my requests for some...had to go back to warehouse to get some...HQ couldn't even see these on inventory...he finally got the one they sent recognized (bless his heart!) but now no channels are seen (V58 error on all channels, before had V56 and V58). No progress before he had to leave despite numerous calls to his tech. He commented there was no MAC address? I am at wits end (and maybe Comcast's end) Supposed to call in tomorrow to see if Office(?) can help. Any ideas? Comcast box works great (of course! ) I hope your cancellation problem isn't mine! Our tech talked to numerous help line people, and several knew we had both sets.