African Bank
Debit on the wrong date

I called African Bank on the 7 February 2013 to change the date of my debit from 25 to the last day of the month as I have changed employers. After submitting the documents requested on the 13 February no feedback was received from African Bank until I called back. I was told to send through my ID which I did on the 23 February. Despite all these efforts, African Bank still debited my account which will have an adverse effect on my credit record. I now need to know what more must I do to be assisted and have the date changed?