MTN does not care - Worst service - Wrong contract - Won't fix its mistakes

I upgraded and traded in my old device so that I could get a R400 monthly reduction on my installment. The upgrade with trade-in did not work successfully and I was paying R400 more monthly since December 2023. Mtn tried to fix it by reloading my contract but this ended up canceling the contract and now I'm liable to pay the full contract amount of R16000. The Mtn store is telling me not to pay the full amount but cannot guarantee that my creditscore won't be affected when the account goes into arrears which it will because who has R16000 just ready to pay up a contract. The service I've received so far is so bad. I've emailed Mtn complaints twice with no reply and I've called the call center to log complaints and no one can help me. Mtn does not give its clients good service. They quick to give contracts but you cannot speak to anyone that can actually help you.