Day light ******* by MTN South africa

I had a data only contract with MTN. when the contract was due for upgrade, I requested for an upgrade but the upgrade was note done. The contract eventually expired but to my surprise, I was now charged more than double the amount I was paying when on contract. I called MTN to request the cancellation of the contract telephonically but that was not done. I went to the store for assistance but I was told that I can only cancel the contract telephonically. I then called the help desk to only be told that the supervisor couldn’t get hold of me to confirm the cancellation (the supervisor was calling the Data only sim that was on WiFi router rather than my primary phone number I provided when applying for the contract). I requested my contract to be cancelled on that telephone call but that never happened while I’m still being charged. I stopped paying and now I was send a bill of over R5000 by their lawyers for the service I have never received, they even allocated the number to someone else.