Fnb debit order **** again

This is the 2nd time FNB is trying to **** me. I have a debit order scheduled to go off on the 27th every month and it does so. I transfered money on the 25th to ensure all my debut orders went through on time for the 27th. To my horror today I have a minus R180 that FNB charged me for a debit order that did not go through on Friday. I told FNB that it was scheduled for the 27 and have proof of that FNB said its not their problem after speaking to Mantwa on the chat App. I don't understand y I have to pay R180 for their own issues. If you dmmt reverse that money I will escalate this to the ombudsman. I want my R180 to be refunded