Fedhealth won't pay for their network hospital

I have gallstones problem and it has come to where it now affects me in a way that I was admitted at the hospital thinking I have appendicitis, finding out that I have gallstones. Asked the Fedhealth medical aid about removing the gallstones, they told me that I should go to their network hospital in order for them to pay, if we go to other hospitals that are not in their network we'll pay half. Now my gallstones removal is scheduled for tomorrow 11 November, I get the call from their network hospital that the Fedhealth medical aid told them that I must pay half for the surgery. We have funds in our medical. I just don't understand why they are trying to scheme me. We only used our medical aid twice this year and they didn't even pay all of the expenses, we had to pay cash. Fedhealth must be shut down. It's a lot of money that we paying and we pay straight from my husband's salary, R3900 is not a child's toy. Now it's the end of the year they don't want to pay. This is not fair. This is my life that we talking about. Fedhealth is risking with my life.