Fnb charged me for R360 as unpaid items whereas there was funds in my account.

It is now the second time fnb is charging me for unpaid items whereas there is money in my account. First time it was R110 I let it go. Now it’s R360 ??? Really I feel this is unacceptable as I know there was money in my account sufficient for my debit orders. I think now it’s time for me and fnb to part ways. And then there’s the banker ??? What’s their role really. She tells me fnb honored the items my question is who asked them to there was enough funds in my account to honor those items.