Thanks for posting to the Xfinity Forums. How are you trying to access the channels, on your cable box, or the Stream App/Portal?
I can help figure out how you can access the PAC-12 Network. In order to do so, I will need to access your account, check your package and channel lineup and verify exactly which channels you'd need to go to. Can you please send a private message including the full name as it appears on the account and your full name if different? To send a Private Message, please click Comcast_Support” and click “send a message.