negative balance on my FNB

I have been a client with FNB and recent i have realize that my account has a negative balance when i contacted FNB the FNB officially explained however i still couldnt get what she was saying because my account keeps on indicating negetive balances from the 4th October 2022, the amount started to indicated -R107, and today (06.10.2022) its - R450, and i dont know tommorow,