Poor service

I took out a contract with MTN S.A in 2018 and I was told that it is a month to month contract that can be cancelled at any time.I called the call centre to cancell the contract and they told me that I cannot cancell because the contract is for 24 months.I requested that they listen to the recording and get back to me I have requested this a number of times but no one has gotten back to me.I am unemployment and I can no longer afford to pay for the contract.They tried tp debit my account and found no money and they are requesting a payment or my service will be cancelled.I cannot have my service cancelled hence I am looking for employment and this is the only number that they can contact me on.I am so ****ed off that no one from Mtn is getting back to me.