Debit order rejected -failing to update my details

I would like to raise a complaint and reversal of the service charges charged on my account because of a rejected debit order. This was after I came into the Canal Walk store and completed forms to update my banking details with a one Lorenzo Castle who assured me that my banking details had been changed. This was not the case, hence the debit order did not go through because the member staff in the Canal Walk Telkom direct store did not do what they were meant to do rather what they promised to be done. <br> <br> I demand that the charged be reversed as this was an error on Telkoms part, and my account should note be charged for this. I called Telkom call centre to have this rectifies. As usual the call centre reps put the phone down on me on 3 different calls