Over charged

I have cancelled 2 contracts during the minth of September 2017 which includes paying the premature cancellation fee. The quotation was received on 06 sept and payment completed on 12th September. Vodacom failed to acknowledge the cancellation and generated an invoice for October. I lodgged a complaint on 2nd Oct and subsequently the contract terminated on 5th October. However the debit order was not cancelled and a further payment was debitted at the end of October. The data subscription on one of my contracts shows that a bundle was allocated on oct 1st and contract Cancelled on oct 5th. No data was used but the bill at the end of the month still arrived. Further queries to vodacom has beed logged since and the operater managed to remove the debit order. I was advised to lodge a dispute for the reversal of the last debit. Unfortunately the operator service does not allow you through unless you have a valid vodacome number. This is the case because upon cancellation of the contract i ported my number to another service provider. I have been told on 3 occasions that vodacom will call me back within 24 to 48 hours. That has never happened. It seems almost impossible to speak to the correct human being (not operater) who can assist without transfering your call to a department that never answers.