FNB unwilling to reverse incorrect transaction

I made an incorrect payment with my credit card to DSTV and I have been trying to reverse it but FNB is being extremely unhelpful. I understand that the error was mine but surely it can’t be that difficult to reverse a credit card payment. FNB keeps sending emails with incorrect info - first they claimed it was a debit card transaction and then they refer to it as a debit order. After I kept on clarifying that it was a credit card transaction they emailed days later to say they couldn’t assist in any way and I should contact the merchant. They couldn’t be more unhelpful if they tried