I get an error when I try to use "xfinity my account".
what error do you see?
cannot connect , try again
use a browser and go to https://customer.xfinity.com/#/?CMP=ILC_myaccount_myxfinity_au and sign in. does that give you the ability to pay? you can get to it via xfinity.com and sign in then go to your account tab menu at the top.