Unsatisfied customer

I took up an FNB funeral policy. I authorized to foe my debit order to go off on the 27th of each month, however for the month of August I got paid on the 25th as the 27th was a Sunday. FNB did not track my account like they normally do. They chose to debit me on the 28th of August when I had no funds available in my account and they tried debiting on the 31st August 2023. Due to the incompetency of FNB I had charges of R105 for the 28th and R105 for the 31/08 added to my account. When I contacted fnb via the chatbot on my fnb app i was told they cannot reverse the charges and that it is my fault as i did not keep money in my account. I do not agree with this as they were supposed to track my account from the 25th August and not after. I refuse to pay the charges on the account and I want this reversed.