No Customer service for Corporate clients

I have been penalised on my CTI score after MTN has flagged that I have not paid for a business that has been dissolved over a year ago. I tried making contact by going into 3 different branched, no one could help me, they have me a number that I could not get through to. They said that someone will contact me, I received an email from Jack Phiri that just stated an amount that I owe to get my name cleared up, without any statement or any details how to pay it. I emailed to Jack 6 times over the last month and he has not responded once. I then contacted Legal department 5 days ago to try sort this out, an automatic reply said that they'll answer the email within 48 hours and I still have not heard anything yet.