Unable to cancel Xfinity Mobile Service

The online chat is broken and just gives me: "Unable to start a live chat session. Please try again later." and asks me if I want to schedule a callback. I say yes... and it goes into an infinite loop... I have tried different browsers, desktop and phone, with the same result. It's just broken.

I call the phone number to cancel my phone service. I want to cancel the line not transfer it. The AI agent on there also goes into an infinite loop whenever I try to get to an agent. Eventually it just hangs up on me. It's extremely slow and frustrating. I weep for all of the actual humans working there that have to deal with the fallout of this abysmal level of engineering.

Please, how can I cancel this line? I want to keep my internet service but get rid of my mobile line.