Nightmare of a company

I cancelled my contract this year January and kept insurance active. May I received an email from the insurer that the policy was cancelled due to non payments yet I never missed any month to pay. I enquired with Telkom and they investigated and rectified on their side, during the investigation however they kept going to my account for debit order which they didn't find any money because I kept that account empty on purpose. Surprisingly they concluded that I owed them R39.28 which to date I don't even know how it came about, they updated my credit profile to R0.00 but didn't close the account even after sending them emails and requesting a paid up letter. I did by the way pay the R39.28. To my surprise this month I get a statement from them saying I owe more than R400.00 for failed debit orders, they keep going to my account, I sent them countless email and Nhlanhla Tshabalala who assisted before does not respond to any of the emails I send him. I am so frustrated as this is affecting my credit profile negatively. How can I owe debit order fees for the account that is fully paid and Telkom refusing to close the account? Telkom is a nightmare!