Closed account and received written confirmation that no outstanding fees must be paid and for more than 11 months now I am still being harassed by Bonitas and ITC as they claim I have outstanding fees

Closed account and received written confirmation that no outstanding fees must be paid and for more than 11 months now I am still being harassed by Bonitas and ITC as they claim I have outstanding fees. I have handed this matter over to the Medical Aid Council of South Africa and ITC keeps sending me blind emails stating the outstanding arrears have not been paid and due to interest and charges for emails, the amount multip****. ***///ITCBA Account name: Carla Olivier Bonitas number: *** Bonitas keep on stating they will investigate and then turn around and state that I indeed owe them money. I have a written document stating that I do not owe any further fees to Bonitas and this will be submitted in court as evidence.