Fnb won't retrieve unauthorized debit.

The fnb call center service is very slow . My mother banks with fnb , she was debited +R1k 5days ago by 1st for women, the debit was unauthorized, she has now lost a lot of airtime trying to get fnb to reverse it but it seems like non of the people who picks up the phone are capable of doing it. Is the bank not supposed to protect its clients and their money?