PATHETIC SERVICE AND CUSTOMER CARE - MTN

i have cancelled my contract with MTN 2 years ago and have recently found out that they have not closed my account yet and I am listed on the credit bereau with them. I have been into the MTN store in Kenilworth Centre, who advised me to go to Canal Walk, which I did, to be told that I must phone their call centre. I have called literally 17 times to be answered by a bunch of total idiots who were unable to assist me.

I do not owe MTN a penny and would like to know why they are not willing to assist by removing my name.