Telkom wrongly accused me of none payment and now i have a bad credit scoring and they are not assisting in rectifying thier mess up

I have been requesting a letter from Telkom for the past 2 months to remove my name from the credit bureau. Telkom reported me as a none payer for an account I closed in 2016, that was fully paid up. Telkom then reported me to a debt collector this year 2018 January and the debt collector started calling me daily an outstanding amount of R1200.00. I tried applying for a credit card and it was declined saying that I have a default against my name. I then went to Trans Union and Experian for a report and found out that Telkom has said I have not paid then since the beginning of this year for the same account that was closed in 2016. I the started calling Telkom everyday for the past 2 months to request them to resolve the matter and all the consultants can say is that my account is in a credit state (Telkom owes me money) and that they will request a letter and make the required amendments with their credit department. every time I request to go through to the credit department - I get told im not allowed but nobody ever gets back to me. this has really been a serious obstacle and a bad reflection on me with regards to my credit rating. I have been emailing a manager 'Aqeelah Hendricks (A)' ********** from Telkom now for the past 3 days who promised the best service and resolution, however has been ignoring all my mails daily. Not sure how this review will assist but I hope that it can