OVER- CHARGING

I was also in hospital for an elbow operation and was given hand sling. Discover medical aid say they will not pay for this, it must come out of the medical savings account. They are charging me R452 for a sling. The same sling is R79.00 at Clicks. If this is not over- charge I have no idea what it is. I then asked if I pay cash, the then said R350, I then asked why and they said the medical aid is the one that is over-charging me.