Struggling to cancel MTN month to month contract

Hi there, I went to a MTN store in Cape Gate Mall to take out a month to month business contract of which I did. On 14 October 2021, I wanted to cancel this contract because contract because I saw a better deal from another company. I went back to cancel it as they said month to month can be cancelled at any time. I was told to write a cancelation letter with a copy of my ID attached to the letter and send a email to MTN (Email address provided to me from a salesperson in store) that is as easy as that they said. Well I did it, I wrote the letter sent the email as I was told. Believe it or not it's a year later and I'm still fighting about this contract and they want to blacklist me. I will go the legal route to resolve this matter.