Error on credit card update page

I'm trying to update my credit card for autopay. Whenever I log in to my xfinity account and click the "update your payment method" link to go to https://payments.xfinity.com/autopay/edit the resulting page says: 

ERROR
Sorry, this isn’t working right now

Please return to My Account Overview while we resolve the issue.

I've tried repeatedly over 12 hours. I tried in Firefox, Chrome, Safari, on Windows PC and iPhone. Same result. 

Xfinity Support on twitter said the web site is working for them so there's no problem. I asked if that specific page is working for them, and they stopped replying to me. 

How long will it be until that page is working correctly for my account? Should I wait a day? A week?

Is that page working for other people's accounts?

What should I do? I'm trying to give you my money. Do you not want money?