I am fed up with Xbox and there [mod removed] support

So no ones gonna help [mod removed] Microsoft

Hello, sorry you have had a bad experience with Microsoft and their support. Unfortunately these sort of things happen and sometimes they take longer than expected to fix. Hopefully you have better experiences in the future. All the best and try to remain
positive.

The "cannot process payment" is a generic response (to protect the consumer they don't tend to say where the problem lies). If it's still not working you may want to contact your card issuer, they might be able to better see and resolve where the problem
lies.

Depending on where you are located, PayPal may also be an option. If so, try attaching the credit card to the PayPal account and then use PayPal as your payment method and then you should be able to select that card for payment. If it doesn't work either
place then you at least know its the card. I have always used a prepaid credit card for every purchase on my Xbox and I have never had a problem. And I've used both methods as I've described. But that is another way you can to try to process the same purchase
using that card for payment.

Sometimes with these prepaid cards you must register the card and enter the address you want to use for the billing address. Without the correct billing address any payment will fail.

I would try recalling tech support and your bank to see if a transaction actually went through before trying again incase it did charge you. I’ve seen that happen a few times.