MTN Has a poor customer service

I’ve been an MTN loyal customer for years but recently they just showed me that they do not care about their customers! Around June I recieved a call from the MTN Mondo department saying I’ve been with MTN for a while so they want to reduce the price of the data package I have with them, they told me they’ll send me a sim card I will just have to transfer data from that sim card to mine, I was told that it’s just an upgrade fast forward to month end I get a bill showing that It was a new contract not an upgrade so now I have to pay for two contracts, ***** was committed ! I contacted MTN and they said they will investigate of which they did and they called me and said they are done with the investigation I was indeed misled and they will cancel that contract I won’t have to pay for it. Till today they haven’t cancelled that contract I’m just getting billed, they even de activated my sim card I can’t make or receive calls! I’ve been to almost all MTN stores around Joburg for them to resolve this issue but they all say they can’t help me! I am so tired of MTN all I want now is for them to cancel their things and I’ll get a more reliable Internet service provider! From June till now nothing has been done.