We haven't had any reports of similar issues, mauricecunha. Rest assured I'm going to get to the bottom of this so you can update your billing information successfully.
Let's perform basic troubleshooting steps to help fix the problem. Try using an Incognito window or private browser. This is to check if this has something to do with your browser's cache. You may use these keyboard shortcuts:
Ctrl + Shift + N for Google Chrome
Ctrl + Shift + P for Firefox
Control + Option +P if you're using Safari
If this fixes the issue, I'd suggest clearing your cache on your regular browser. This removes any browser history that may have caused glitch inside Quickbooks Online. As an alternative, you may also try using other supported browsers. You can check it here.
I've added these articles for additional reference: