Gems gives authorisation but does not pay

This year has been the most difficult one because of Gems.. I don't know how many reviews I've done on them.. I've made endless calls to gems and nkw they are even ignoring these reviews. My dad was scheduled for admission some time in August to do a certain procedure.. When we arrived in hospital gems refused to authorise. That was about 3 hours drive to the hospital. We then left and drove back home. Half way through we got a call from a certain guy from Gems underwriters who told me to return to hospital and even sent the doctor and hospital an email with the authorisation.. We went back and dropped him off. Everything seemed fine and the procedure was done.. After a couple of days he was discharged. Now maybe 2 months later I'm getting a hospital bill of more than 10.000 from the hospital because Gems never paid. Why are they doing this to us? Why do they authorise and not pay.. Why have they put my family through so much.. Or maybe they want us to cancel our membership.. Why tell us to send our dad to hospital and then not pay