Penalty fees for good custumers

I’m totally disgusted with FNB. Two debit orders went off my account that was less than R80. There were no funds in the account and I had to pay R240 for penalty fees. This is not acceptable. We are old customers banking with FBB for years now and this is how you treat your customers. I put the money in my account this morning. I feel you could at least gave as a day or rectify the problem but NO you take our money without a warning. My husband get pension money. We have an excellent credit rate and we have car finance with Wesbank. Really give out money back. Your system is so delayed when you swipe your money so you never know how much money is in the account and this is why this things happens.