MTN c onsultant **** and now I'm struggling to cancel my contract

I have been trying to cancel my contract with MTN and have not been helped by any of the call centre agents. They are all useless in my opinion. I was **** to into accepting the contract ( the person who did this should be fired). I was offered 80GB anytime data but was notified by someone else that it was 40GB. I need this contract cancelled asap. MTN has sent me in circles trying to get this contract cancelled but to get the contract they would hound me continously