Members on Medical aid being held liable by healthcare providers lack in billing

I am really irate with the healthcare provider (Vital air) and the way members are being held liable.... My dad received a letter to inform him that he owed Vital air monies for materials supp**** from 2014, One month they bill via the hubs and switches and then the next month via paper and will then pay or reject if they bill correctly, Or materials will be billed on an invoice send to the member via postal address and then not submitted to the scheme, keeping the member liable. THEN BEST ONE OFF ALL........ please note: we have submitted the claim on your behalf... even the disclaimer is a lie.... meaning this disclaimer is null and void... If your Medical Aid covers the benefit and you have all the approvals for treatment, then clearly if you the healthcare provider do not have a clear process with the schemes administrator's, Stop keeping the members liable for your lack in billing correctly....