Bad Service and unrealistic contract terms

I took a month-to-month contract with MTN in 2023, the contract did not serve my purpose. I then called MTN to cancel the contract, and I told to pay one-month outstanding fee which I paid. I called again to cancel, the MTN told me that I cannot cancel the contract because it is 24 months (month-to-month). I never used this contract since the last payment. Now, MTN says I owe them R2800 for the remainder of the contract that they could not cancel. So it accumulated for the remainder of the contract without being used, so much for a month-to-month contract that can be cancelled anytime.