incorrect billing no response from vodacom

My contract effectively came to an end 1st March previously I contacted vodacom regarding this , as the contract officially comes to an end effectively the device my iPhone would be paid off and therefor I should have a debit amount less the amount for the device , they responded advising I was correct . Since then I have been debited the full amount including the amount for my device despite it being paid off <br> <br> And further more I have just recieved my statement for the end of this month and the debit states the same that I will be required to pay the full debit which is obviously incorrect <br> <br> I have mailed vodacom no less than 3 times and had not response , it's a disgrace that they choose to ignore the problem the need to reimburse me the amount taken off for the device at the beginning of this month and change my billing going forward