I am in the same situation as you. I have been unable to contact the live customer service every day for a week. What is wrong with the service?
If you're stilling having trouble getting a live agent, this is what worked for me - call Comcast and go through the options as if you were adding a new service. That will connect you to a live agent (I guess that's how they're prioritizing customers!), then you can tell them you don't actually want to add a new service and that you need their help with XYZ.
This was the only way I was able to catch a live agent who could then transfer me to the loyalty department, a department that you can ONLY reach by phone.