FNB deducting money not rightfully theirs.

When I first joined FNB, they allowed small debit orders to go through and gave you a day or to two to ensure funds were in the account. I do not have a fixed income. I get money through PayPal which FNB needs to clear and they don't always clear it when they are supposed to. I had debit orders scheduled for the 1st. My PayPal funds that were meant to clear on the 30th only cleared on the 1st. But they will tell you that PayPal won't clear on weekends or public holidays. My debit orders went off. My funds cleared 2 hours later. After the money was clearly on the account, 2 of my debit orders bounced. I had to phone my insurance to ask them to resubmit. Which they did today. I saw when one of the two debit orders bounced yet again, that FNB had charged me R175 for those two debit orders that rejected. And another R75 that rejected to say. And, guess what? PayPal funds cleared again in my account a couple of hours after the debit order went through. And was again rejected after. Why should I be penalised because FNB does not clear my funds on time? I just sat in the bank now to get this resolved and I was told that they will refer it to their reverals department and they will let me know within 2 to 3 working days. I need that money now. I don't earn a lot of money. FNB takes what they believe is theirs instantly. Why must I wait, when FNB is clearly in the wrong? On a previous occasion when this happened, FNB apologised and reversed the money immediately. Now I just wait. Not cool at all. If I were not bound to FNB because of PayPal, my account would be closed already.