Remaining Reward Voucher Disappears

I recently work very hard at achieving my weekly target in order to get rewarded with a R500 voucher to spend at Cape Union Mart. I received the reward and added it to my wallet on my iPhone. Nothing was mentioned that you need to spend the full amount of the voucher in one go or else you will forfeit the remaining amount. Not knowing this, I went and purchased a cooler box for R250 and was under the impression that the voucher would now have R250 remaining. This was not the case and the R250 just disappeared. After calling Discovery Vitality, I was informed that this is mentioned in the small print. Of course, it will be in the small print. Any way for Discovery to ***** over their customer and save a buck here and there. It is an absolute joke and it should be very clear at the start of downloading the voucher that this is the case. Very poor service from this organisation and very frustrating! Maybe it is time to look at moving to another medical aid and shutting down my bank account with them.