Unauthorized Debit FNB

I have just noticed that there is a debit of R120-00 from my account. The account is on minus. The deduction if is from PMT Honfree. I do not remember joining something like that. I don't know why FNB allowed this to happen without notifying because it is an amount that is more than R100-00. My account was on 00 because i knew that all my debit orders have been ordered. This is reckless from FNB because it has become a norm in my account every month to have this unauthorized debit orders. I think it is time i move my account. I cannot be every month monitor what is happen in my account. it means my account is not safe with you guys.