*****ulant account upgrade

I have a cell phone contract with MTN which has been **********ly upgraded. I immediately called the MTN call Centre to notify them of this and got this ref number: ***. I have since been to the MTN branch at Westgate Mall more than three times to have the matter resolved and it seems as if the ***** department is dragging it's feet on the matter. The store personnel have sent e-mails as well as an affidavit stating that the account was **********ly upgraded and there has been no response from MTN in over 2 months. This upgrade has caused MTN to deduct more than double what they were initially deducting on the original contract and this is a huge inconvenience. I am not happy with the lack of communication as well as no sense of urgency with regards to the matter especially since I have to foot the bill for their mess.