Unhappy customer

I must say I'm really frustrated with the way FNB does things. I woke up to being charged an excess fee. When I asked I was told that unfortunately, that's how the bank works if I had pending transactions. How's it my fault that merchants did not debit on time? Why should I be held accountable for that? I always get ridiculous debits even amounting to R20 for withdrawing at an non Fnb atm. I'm really not happy with the way things are done. I've overlooked the small amounts but now this is getting ridiculous.