Vodacom did not cancel my debit order

I called to cancel my contract after my contract duration had ended and 2 months later I am still being charged. When I called to cancel the guy told me that the debit order was cancelled and I wont get charged. After the first debit order I assumed it would be the last but then the 2nd came off. Now after closing my bank account it looks like I have not paid my debit order so of course this will look bad on my credit score when my wife and I are trying to start a life. I went in store to try and sort out the issue but they notified me that the only way is to call the number ***. I called the number 3 times and each time got cut off and could not reach a representative of which I have recordings.