Bad Service - Money tracking - Charges

Can you please kindly reverse the debit order reversal charge. I have a personal loan with FNB, the collection day last day of the month, so this month September FNB collected on the 22nd which did not make sense to me as there was still a full working week before the collection day. On the 23rd wanted to use money in my account only to find it has been deducted by FNB, I asked for it to be reversed as the debit order is supposed to be tomorrow 30 September but because it falls on a Saturday I understand if the deduction goes off today. You will notice last month which is August the money was deducted on the last day, any other month if it is before it is because of this tracker that FNB uses, before May if you see 25th as the payment date, it is because I took the loan when I was still paid on the 25th, I called the bank to update the information to the last day. The main reason I am here, is because Siboniso Gumede stated it was my choice to reverse hence the charge, and my argument is that I get charged when I don't honour my contract, now why should I get charged as well for FNB not honouring the contract, does FNB even understand we have other commitments not every money in the account is theirs.