Claiming more than once from medical aid and then requesting a full payment on account

I went for blood test and not soon after i received an invoice from Vermaak and partner asking to settle my account in full, they said that the medical aid did not pay any of the blood test. I kept on receiving accounts from them and even a final demand being threatened to be handed over to debt collectors if I do not settle my account.

When I contacted my medical aid they said that Pathcare claimed my blood test multiple times exhausting my benefits. Discovery paid the invoice twice and therefore did not want to pay for the third claim. Eventually my medical aid called them to try and get it sorted out on my behalf, I received another final demand without any apology or feedback regarding their wrongful invoicing. So they are *****ing benefits from medical aids.