Indebted by discovery medical scheme

I joined discovery medical aid this year in April, it came highly recommended from a colleague in July I got admitted in hospital due an emergency, I was diagnosed with ulcers and was admitted for 3 nights, now discovery medical aid refused to pay the claim, firstly I never planned to get sick but the medical aid alleged I have joined their medical aid because I had a pre existing condition, now I am sitting with a debt amounting to R 14000 Secondly I have discovered that they are deducting R 4100 instead of R3800, on top of that last month they have deducted an additional R637 from my salary Now I have to pay a debt while paying medical aid which is overcharging me, thanks to the lady who assisted me today, she really opened my eyes This is daylight to *******