Refusing to settle the bill

My wife gave at waterfall Hospital, the hospital submitt the bill to the medical aid and the medical aid didn't pay the whole amount. We called gems and the hospital did the samething, in conclusion they promised to settled the bill after we submitted all the necessary document, later when we do follow ups they came up with stories. hang up the phones at us. Beginning of September we were told that they will pay the outstanding amount month end, when we call them the stories changes again, someone at gems is failing to do their jobs