FNB system error resulting in unpaid penalties.

Hi, for almost a week now since I have logged a complaint with FNB and I am yet to get a response or an acknowledgment of my query receipt. On the 1/10/2020 at 12:24pm FNB sent me an sms apologising for their system error where my debit order did not go through resulting in an unpaid debit and the supplier penalised me with R70 for not honouring my monthly payment. However FNB reversed their R110 penalty as they noted an error was on their side. A month later, my swipe transactions are not debited from my account immediately as usual and kept as pending until the merchant banks their machine. FNB only processes transactions a week later resulting in a negative account and they still charge me with an unpaid fee yet funds were available at the time of the transactions/ purchase. I need the penalty fees reversed and my account rectified. Someone please explain the reason for such as it is not the first occurrence and advise on the way forward to prevent such inconvenience. Katlego Mabasa ***