Failure to inform

My mother in law was admitted to Mediclinic in Secunda with a breathing problem on the 27th of August at about 04:00. My wife and myself used the medical aid which we started with Discovery Health in April 2015. Mediclinic accepted the card and started to treat her. After being in the ICU unit for 4 days, the hospital tells us that Discovery Health does not want to pay the bill. If the medical aid was not valid, it should have been picked up immediately on Friday the 27th. We were only notified on Tuesday of this issue. Now we are sitting with a bill of R83 000. I would like to know how is this possible. Membership number ***, Mrs M Govender. I do know of a waiting period of 1 year on issues relating to a stroke that she had about 8 months ago. This issue was a respiratory issue and nothing to do with the stroke. How can we trust medical aid companies that fail to assist the community.