Debit order reversal

I am failing to understand why FNB does not want to assist with debit order reversals. In this trying time we all going through, FNB decides to not assist us. It is my hard earned money and a debit order of R4500 severely affects my household. How do i call the service provider that debited if they are not an essential service and they are closed? I will be changing banks definitely, APPALLED by such ************ ********* behavior from such a reputable institution.