Can’t Access My Account Info

When I log into my xfinity mobile account it says I’m not a customer? But I’ve had service for over a year. I called and tried to get this straight and talked to someone for about 30 minutes and then was transferred and told there was a 3 hour hold time….call me crazy but I don’t have that amount of time to dedicate to a phone call. I need access to my account so I can update my card info because my old card is turned off but since I can’t do that, I’m late on payment and have a few more days before they cut off service. Also tried doing quick pay and no matter what card I use that isn’t going through either 🙃