Treated like trash and needs to suffer for incompitance

So MTN had handed over my accounts in 2018 to some company that doesn't exist and then it was my duty to get the exact attorney which was handed over to. I settled the accounts in January 2020 with Shapiro Shaik. Now MTN decided to reactivate my account they never explained to me the process as every time when i called them they would tell me to consult Shapiro Shaik.

I have been receiving statements that i still owe MTN and when i called them last week i was only told that i was suppose to call them after settlement. The lady I spoke to last week Fri told me Legal will call me latest yesterday and she told me I need to settle the balance which i am not going to do because I have a paid up letter, HOW WAS I SUPPOSE TO KNOW I HAD TO CALL TO CANCEL THE CONTRACTS WHERE ELSE NO ONE SAID ANYTHING ABOUT THAT TO ME FROM THE BEGINNING? I need my credit profile updated because now instead of it it upgrading it is downgraded.