Ever since the last patch in both CO and STO the chat channels have seemed to be buggy. I couldn't see any at some point, but they seemed to come back. Some people have had no issue either, no idea whats up :(
I can't access any of my custom channels in-game, including all of our channels. This appears to be a problem with quite a few people and affected CO yesterday.
Although, I am still able to access them on Pidgin. If you're experiencing this problem as well, I'd suggest that you set up Pidgin to access in-game chat following this guide.