Unwillingness by MTN to cancel my contract

Hi, I would like to raise my disappointment regarding the contract that I took with MTN. On the 19th of February 2021 I was contacted by a MTN Mondo agent who said they are offering me 30 gig a month at R89 pm contract. The deal sounded too good for me and I accepted the offer. The problem starts when MTN deposits the data as agreed. Only 20gig (once off I was told) is deposited and R120 airtime. This is something that I never agreed to. I phoned MTN on the 9th of April to raise this issue. One of your agents says there is nothing that can be done to change the situation. I even suggested that they listen to the recordings, but she said there is nothing that can be done. I then contacted Mondo via email and phone calls, and they promised to cancel it with MTN.

Fast forward to August 2021, this contract is still not cancelled. I have called MTN and was transferred to Retention department and they said Mondo and MTN should have cancelled this contract but the lady I spoke to hang up on me without telling me what I need to do. It is worth noting that I reversed the debit order for the month of July and I was therefore blacklisted and my name and credit score was badly affected by this. This SIM that was provided to me is no longer in use, I threw it away as the contract was supposed to be cancelled.

Kindly assist with this contract. My details are as follows: Name : Lungisani Magwanyana Number: ***