Over billing on contract

I’m so disappointed with MTN South Africa, I have a contract with MTN which I defaulted due to retrenchment, I called MTN to ask what can be done as from August 2024 I won’t be able to pay but I’m willing to pay as soon as I sign another contract, the consultant did advise that’s not possible as I need to pay each month even if I pay an amount lesser than what I’m debited, unfortunately I was not able due to unemployment, February this year I called MTN to ask that they debit from March as I’ve signed another contract and the amount which I owe I will pay aside, they said that’s not possible and I should pay the full amount all at once which I don’t have, they then sent me a pre-cancellation email which stated I must pay the full amount of R11967.3 at once which I didn’t have, I sent emails to their legal team where they now said the amount remaining is R17779.05, and for the contract to be reinstated I must pay an amount of over R9000+ at once which I still don’t have and I told them I will pay for the device alone without data and airtime as I can’t afford the amount they are insisting I pay, the balance remaining for the device is the one they sent on their first email of R11967.3 but now they want to me pay extra money for data and airtime I didn’t use which I did state I don’t want it but I can pay for the device monthly, instead they took my account to NuDebt who are now demanding I pay R18447.20, I don’t have the money they are demanding from me and they are refusing for me to pay for the device alone which I did state I can pay it in monthly instalments, I’ve sent emails and emails and they just responded by stating that my account has been handed over, it’s so disappointing, the consultant I spoke to even stated that I used to pay my account on time before I lost my job and I was willing to pay the amount remaining for the device alone with out MTN’s data and airtime but they want to ****** money from me which I don’t have.