When I go to change it there is no field to enter my new credit card number, no blank area to input the new information. It lists it in text on the left, but again there's nowhere to input it on that line. As for contacting support, it asks me to sign in with various services, PSN, steam, XBOX, switch, none of which I have. I'm playing the game on a PC.
I tried IE, Chrome and Firefox, for all 3, after I sign in it asks me to sign in with one of those services and I don't have any account with any of them. Maybe, I'll try in-game support
I was able to submit a bug report with my email address, the in-game help just brought me to the same screen.