FAILURE TO CHANGE BANK DETAIL

I went to Vodacom to change my banking Detail but they could not assist me at the store.<br> I was given a contact number for the admin department which I contacted on the 18th of October 2015<br> They informed me it will take 3 days to process the application but I can also e-mail the detail to the admin office.<br> <br> I also mailed the detail through and were suppose to get feedback within a day<br> To date I had no feedback from the telephonic request or e-mails that was sent.<br> <br> The deduction is still going of from the old account.<br> <br> I don't understand why they are not competent to change the bank detail or at least reply on my request.