Discovery are thieving ****s

I'm utterly appalled at benefits (or should I say Lack thereof?) that i'm being cheated out of left, right & centre. I was diagnosed with colon cancer 5 years ago and have luckily been clear since my operation in 2014. I was advised by my oncologist, gastroenterologist and my surgeon to ensure that I do a follow up Gastroscopy and colonoscopy in 2019. I was informed by Discovery that I need to pay a R4500 co-payment on my preventive scopes unless I have it done in the Doctor's rooms (from specialists I have spoken to, to have the procedure done in the room is not really an option due to space, discomfort to patient, etc) Oncology benefit won't cover the scope because I currently don't have cancer. Seriously? Instead of covering a procedure that will in essence SAVE discovery a potential R200 000 oncology cover, i must fork out nearly R5000? Money that I, and most people don't have floating around due to the INSANELY high monthly premiums we pay for Discovery to cover our medical needs?????? Help me understand why I should stick with Discovery