Changing of debit order dates for December! FNB HOW CAN WE INCONVENIENCE YOU

Every Year ! Every ****** year for the last 3 year I'm having this fight with FNB. Please inform me where I gave consent to change my debit order dates earlier in December. I DON'T WANT MY DEBIT ORDER DATES TO CHANGE. THEY MUST REMAIN AS IS FOR THE MONTH OF DECEMBER. As soon as my debt are paid I'm moving away from this dump fire which calls themselves FNB