FNB Credit Card Debit Order Issue

My Husband's Credit Card Payment is deducted from him Cheque account VIA Debit Order each month. This month his Cheque account has been Debited as per usual for his Credit Card Payment, we can see on his Transaction History the Payment was Credited back to his Cheque account for some reason, but the Funds are not reflecting in his Cheque nor Debit Card Account. FNB keeps messaging and calling him to pay his Credit Card Account, but one way or the other he has paid and the money is just not reflecting anywhere, meaning what is the money gone? Receiving horrible service from Secure Chat Agents, no one is able to assist. This is absolutely pathetic, putting his account in bad arrears, an he has not received his money. He's had this account for such a long time, so we know how payments works and when payments are usually deducted, so this is the first time something like this has happened. Extremely unhappy with FNB Customer Service and Care and the Product overall. Would not recommend to anyone. Can anyone at FNB assist?