Poor service

My memberships was recently terminated by this medical scheme. The reason for cancelling was that they said I did not disclose treatment received for ADD. I did not understand this as I had not been treated for said issue. I contacted my doctor to find out how this is possible. It then came to light that the doctor had accidently entered the incorrect ICD-10 codes. The doctor corrected the mistake and I sent the correct statement to the medical scheme. They responded by saying it does not matter if it changed, treatment was still received and I did not disclose that. How can I disclose treatment for ADD if it did not happen? How can the termination still be valid if their reason for cancelation has been corrected by the doctor that made the mistake? surely if the material facts for termination change, the outcome must also changed. I have since tried to get in to contact with someone that can help me but was told it is not possible, only via email, which I have done but I do not get any response. It is pathetic that we pay so much per month and in an instance they can terminate a membership without doing their due diligence and completely ignoring the correction that I have sent to them. So at this moment neither me, my wife or our daughter are covered due to their poor customer service? Who is liable if something happens in this time and I can prove they terminated my membership without grounds?