Hello there;
I just wanted to add some additional information that may be helpful when resolving your issue about updating your payment method.
If the previous advice doesn't resolve the issue, you may want to consider clearing your browser history prior to logging on to your self-serve account. Then you go to update your payment method, your browser well except the new information that you put in.
Sometimes it's helpful to look at the entire page prior to making changes to your account in your case it would be under the payments tab.
If you're unsure as to where to find your history options depending on the browser you are using it may be located in different places.
Assuming that you're using Windows 10 as well as the Microsoft edge browser, you can click on the three dots in the right-hand corner at the top of your browser page once it is open, click on the history option and choose what you want to clear. If you are using a different browser like Internet Explorer normally it's found under the general tab wants options have been selected from the sub list.
I hope this was helpful!
