Incorrect Debit order

On the 26th September i call multichoice and instructed them to downgrade my current Premium package to compact package .I instructed them to make sure that this is done immediately as my debto oder was going off on the 28th which whouc have been the new compact premium .To my surprise they still debited the full premium sub and i still had the premiun package .Fine ,i call again and a lady aissisted and informed me that i would be charged prorata rate and the balanace will be refunded to my account .I still have not receive my refund but my package has be downgraded. I called again this morning and now i am told that i must go to my bank and asked them to reverse my dr order because i had an existing credit on my account i should reverse the entire debit order .I am not prepared to do that and want dstv to refund my money into my account .