Failed purchase from microsoft store

Question

I tried purchasing the 2000 credit bundle for Halo Infinite from the Microsoft store. On selecting "buy" it returned an error message, stating I have insufficient funds to make the purchase and that it had been unsuccessful. I tried again once or twice, but the same thing kept happening. I closed the tab and went about my day. Now I see the ZAR300 has gone off on my bank account, but I have nothing to show for it. I checked my emails for some confirmation of purchase but to no avail. I checked the in-game store to see whether my credits are reflected there, but even after restarting the console and game several times, it does not appear there either.

I tried the Microsoft support but it did not give any helpful advice and neither the web chat or calls are available at present.

Does anyone have any advice?