Cancellation of contract

I called in Feb 2023 requesting for my contract to be cancelled, someone called me last week saying I am owing over R900. Today I have been on the phone with MTN the whole morning sent from pillar to post no one to take accountability, some even cutting me off whilst am still talking. As much as they say they can see my cancellation request on their system, They say contract was not cancelled its still active hence am in arrears. I asked them to cancel it once again, they say they can’t because I am owing , I have to pay first. I refuse to pay money for the contract that I have requested cancellation for in Feb and cancellation request is on MTN systems but has not been processed.