Terrible service trying to cancel contract

Terrible experience with MTN, I requested the cancelation amount in December 2019, to cancel my sim only contract via email to which I got a response but I did not have money to sort out straight away so early in 2020 I request the amount again and I get no response, many months later. I called in to get clarity, my call duration was 25 minutes and I had to speak to 3 different people and verify my details with 2 of the consultants only to get told that I cannot cancel because it's within term. It's a SIM ONLY contract so I AM entitled to cancel but the last person I spoke to, Desmond, refused to assist. I have since emailed the retentions email AGAIN and no response. TERRIBLE CUSTOMER SERVICE!!