Disappointed with Discovery Health

Discovery has declined a specialist visit for me. I am pretty healthy and don't cost Discovery much - in fact I am a good, profitable client of theirs. Years ago I had a medical condition which was quite severe and demanded specialist attention. That is now sorted and I would like to re-verify it is sorted by re-visiting a Specialist and Discovery declines the visit. I get so frustrated with this and find it grossly out-exchange. They will pay huge amounts once a condition is diagnosed, but won't approve a screening visit, saying that my GP can do the screening. I want to visit the Specialist - not my GP. Very very frustrating. I run into this with Discovery every so often and wish I could do away with Medical Aid. Not sure this will resolve and I will pay cash for the visit but I just had to voice my total disapproval and disagreement.