Billed for Nedbank's error

On the 21st of September I swiped my c/card and it was declined. Knowing I have funds available, I contacted Nedbank and it turns out there was some issue on their side. Within minutes, I had funds available again. I was still charged for my card being declined. I have now spoken to 2 representatives from Nedbank and nothing has been done. I even had to help the one representative calculate my available balance... Promises to be called back which aren't kept. Reverse the charges for your mistake!