Contract

I had a phone and WiFi contract with MTN, last year I called in to settle my phone and I was given a settlement letter and made a payment towards the account as I had promised, my WiFi contract got handed over to VVM and I settled it as soon as they called me and MTN legal team gave me my paid up letter. To my surprise I get emails detailing that I have outstanding fees and smses telling me that I need to pay. I send the communication to the legal team since last week and to this day i haven't received a response. I called in they transferred me from department to department without a solution. I want to know why am I getting these emails and smses when I am no longer owing them and they are not appering on my credit report. I need for these accounts to be closed.