Shortfall payments

My daughter was hospitalized at Mediclinic Medforum, post operation. I was and still under the impression that Medforum is contracted with Gems and that gems covers 100% of hospitalization. I have been recieved g statements that I need to pay R6900 to the hospital as the hospital claimed more than the scheme rate, How possible is that the hospital can charge more than the scheme rate?

Gems is becoming a ****, even with my daughter's dental operation I had to pay R7300 to the dentist even when the procedure was done at a hospital? Both Dr and Dentist are contracted with Gems but the top ups we pay are ridiculously high and pathetic...Why get contracted with hospitals and still be unable to settle the bills yet we pay the medical aid every month