Paid with no funds fee incorrectly charged.

My bank account does not have overdraft facilities, therefore I cannot pay anything with my card if I don't have funds. Since FNB does not update our account in real-time, I will pay using my card and the transaction will go through since I have funds. But then when FNB processes their bank fees and they will charge me a "Paid with no funds" fee of R45. This happened in June and July. I contacted their chat services but no one is helping me.