Unable to update payment method,

It is ironic that Xfinity is an internet provider, yet their web site is utter garbage. Every page takes an eternity to load, and trying to update payment method fails over and over again. 

I just receive a notification that my credit card is about to expire, and I need to update the billing account. Yes that is true. The problem though is that the web site is terrible, and I am not able to update my account information. Every time I attempt to update the account I receive a "sorry this isnt working now" error message