Sorry for resurrecting this thread, but just ran into this issue tonight, and it seems to be getting worse, at least for me.
Whenever I step away from the game, I remove my credit card info. Until a couple of years ago, I had no problem adding a new payment method through Firefox.
Then, suddenly, I did. I de-activated stuff like NoScript, Addblocker, etc., cleared my cache and history, etc., etc., and still was unable to add a payment method. Considered turning off my firewall and antivirus, but instead, I tried to re-up through Internet Explorer - and had no problems doing so.
Stepped away again after a few months, returned about a year ago, and again, same problem - only this time the Internet Explorer option didn’t work either. Tried adding a payment method on my phone, and hey, look at that, it worked just fine.
Stepped away again about half a year ago, decided to re-sub tonight. Couldn’t add payment method through Firefox, Internet Explorer, or my phone (even with all the cache and script tricks). I installed Chrome on my desktop, and presto, no problem adding my payment method through Chrome.
Kind of wondering what will happen next time. Seems like I’m running out of browsers and platforms…