Unauthorised debit order

On the 9th March i called avbob to change my debit order date from the 15th to the 20th and Mavis assured me that its change cause she confirmed it with debit order department .but on the 16th March i was debited i called avbob again spoke to jermanine he advised that mavis send the request on the 10th march hence i called on the 9th and i was assured.<br> <br> jermanine advised me that the will be another debit on the 20th which i initially agrred to but the one on the 16th i dispute it because i change my debit order on time before the mag tape..and now i have to pay bank charges for the