co -payment charged for approved hospitals

I had always been a patient at brenthurst hospital since it was on the medical aid's approved list of providers. I had an admission in June and the hospital contacted me saying that my medical refused to approve admission because it said that brenthurst miraculously was not part of their network anymore. I called into the call center and spoke to an agent and explained to him that the hospital was always part of the network and I do not know how it could no longer be. I sent an email to the medical aid explaining this and promised that the matter would get looked into. Just today I got called by the hospital accounts department notifying me that I owe them the r5000 shortfall/ co-payment that my medical aid did not settle. Why am I paying for a service that I am not getting??!! Medical aid sets network hospitals then adds and removes them as it pleases them without informing member's?..<br> The newsletter for 2016 has a list of networks on it... brentrust is still on the list. I would like to know why I was asked a copayment?? Why my matter was never looked into and why I am owing the \network"hospital a non-network hospital copayment fee??!!!"""