Hoax upgrade dates

I upgraded in August 2021 due to my account being so high every month. I was told 2 months I still will have to pay the full R1600.00 a month to make up the 24 month contract. When I phoned today, 25 October 2021, I was told untill end December. I did not sign a 36 month contract. I have been retrenched in the meantime and paying my phone with the little bit of money that is coming in. This is now the 2nd time MTN is doing this to me. Why do we get upgrade dates but still have to pay an old account 6 months after the upgrade. Can MTN come back to me seeing that their managers is NEVER available when you want to talk to THEM!!