unable to make payment

Ah, I've had this exact problem a long time ago. I couldn't add any payment option... I had a small chat with Daniel from the support, I gave him the info he needs, and he said it can be escalated to the Advocacy team and get it fixed in 2-5 days. In about
3 days, my account was updated, and everything worked fine, after I've had this trouble for a long time. Try chatting with the Xbox Support, and see if they can help you with this issue.

I should add that I was able to make purchases a week or two prior to this.

I have almost this same issue. Try buying the game you want from your console. I've noticed you can't buy anything from the marketplace online because you can't use your Live account balance there, but you can use it if you shop through the Games tab on
your dashboard.

Umderstood. But the question /problem remains. Im still unable to use my phone to make the payment. Which was the issue all along. Im unable to edit any info at present

This message appears - "Unable to authorize payment method. Make sure that the correct data is provided, or use another method of payment. If you continue to receive this message, contact your financial institution"