Charge rate different to contract rate

<p>Four months ago I took out a upgrade. I signed a contract and the monthly debit order was on the contract for the same amount as the old contract. when relieving my new statement the amount I have been billed is more than my contract signed. I have called Vodacom at least 4 times. They confirmed there was a problem but stated I need to go back to the shop I took the contract out on. I went back to the local shop, all done via email. It was confirmed that there was a error and that Vodacom had said to the shop they will refund me and correct the contract debit order. Two months have passed and still no refund and no correction. How can Vodacom do this? I have not been billed correctly from the moment that I have taken this contract out! From day one. Do not recommend Vodacom </p>