Bad customer service

Hello Peter I had a contract with MTN of which I cancelled within the cooling off period and they never responded on time . Instead I had to follow up on the cancellation but then I was charged a fee even though I never used the sim and I cancelled within the specified period. Recently when I checked my credit report , I saw MTN as a default and I have been handed to lawyers.Fine I paid the amount owing last week till now I have not received a call from their legal department as per request so they can clear my name and that account. Please assist