Account Fee changed without authorisation

ABSA has changed the deduction date of my Account Fee, without contacting me. I have spoken to some woman, who emailed me an explanation. This explanation is not satisfactory to me and I rep**** to her email, she hasn't bothered to answer. I want the Account Fee to be deducted from my Cheque Account on the last day of the month, ABSA is deducting this Fee on the 26th of every month.....NOT acceptable.