Discovery Dentistry Refund

DISAPPOINTED!!!!! I took my son to a network dentist +- September. The dentist gave me a quote, which I got authorization for at the medical aid. I had to pay cash every time, and according to the dentist's office, the medical aid would then refund me. I have 3 invoices, all paid cash, which I am not being refunded for! I have sent NUMEROUS e-mails, and every time there is one or the other stupid reason why I am not being refunded. I want this sorted out, ASAP!!