Healthcare refuses to refund my money

Would you please assist, I got a claim from the healcare ER Consulting INC DRs Holt & partners that I needed to pay them R1144.20, and I paid it when I checked the claim from my medical aid it indicates that the medical aid has paid R766.30 and i should pay 377.90. when I enquire with them they say there is no refund for it was my responsibility to pay the whole amount, if it was my responsibility to pay , why were they claiming from my medical aid. I have sent them my proof of payment including the statement from the medical aid to show they were overpaid. I should getmy refund of R766.30, these institutions are taking people for a ride.