Wanting money from me and the doctor

So due to incorrect details at the doctors my account bounced with med aid and my number on file was wrong, however when you book an appointment with the doc I gave my contact number (the correct one) as one does....but they only got hold of me after med aid claim period.

I then was back and forth with medical aid and incorrect coding from the practice etc - while being handed over to LexMEd in the mean time - eventually I paid both my bills so according to the practice my account is clear. LexMEd still want over R500 for their admin. HOWEVER, they bill the doctors rooms for the admin of sorting out accounts. So why are you billing me as well??????