Hi ndams,
Thank you for contacting the Microsoft Community.
I understand that you are having issues with your payment method and I know the importance of having this fixed to have a smooth and successful registration. Allow me to extend my assistance to have this resolved.
As per Pearson VUE FAQs, the accepted payment methods are debit or credit cards from Visa, American Express, or MasterCard.

Since you already tried Visa card and received an issue, it is best contacting Pearson VUE support team as they can provide other payment methods that you can use in scheduling your exam. You can reach them out using the link below and select your correct region:
Please let me know if further assistance is needed. I'm more than happy to help.
If this solves your problem, please indicate “Yes” to the question and the thread will automatically be closed and locked. In case we do not receive a response, the thread will be closed and locked after one business day. Please be advised that after the case is locked, we will no longer be able to respond. If the resolution provided did not resolve the issue, please post a new question.
Sincerely,