Cancelation of month to month contract

I entered into a month to month contract with Cell C and requested them to cancel the contract. They told me they converted the contract to a 24 month contract and could not cancel it. After numerous calls to their customer service department I got no assistance. I received a call from their collections team 02 June 2022 11h10, spoke to Nomsa and I requested the email address of her CEO, she said she doesn't know what the email address is and hung up on me. I don't know how to proceed with this company, I have 2 other contract with them, which will definitely be canceled when possible.