Feel like being cheated by Discovery Health

Feel like being cheated by Discovery Health:I have been member of Discovery health hospital plan more than 5 years and never claimed any amount so far.Now I need to undergo a surgery for my wife and requested pre-authorisation where I was asked to pay R5000 compared to the quote provided by the doctor.I am not getting a valid explanaton of why it is 100% covered when I am covered for 100%.Also the Doctor is cofirming in a written quote that he is quoting only 100% discovery rate.I have been struggling with DIscovery to get the clairty for last 2 days but in vain.I feel discovery is cheating us.I have paid around R200K in last 5 years without any claim and still being treated like this.Can someone advise how to take them to legal action towards this?