Cannot use Discovery miles to pay for Kulula flights

I have over R12 000 worth of Discovery Miles. On the Discovery Website it states that you can spend your Discovery miles to pay for flight tickets on Kulula.com. However, now I want to make payment for my flight tickets and Discovery Miles is not a payment option. According to Discovery Card and Kulula, you HAVE to be a Vitality member to pay for Kulula flights with Discovery miles? I don't expect any Vitality discounts on my flight, I just want to use my Discovery miles that I have earned, to pay for my flights. Why is this not possible? Surely there must be a way. Now I have lost the money that I already paid for accommodation, because I cannot pay for my flights to get there. I was planning to use my discovery miles to pay for flights which I now can't do and I don't have any other funds to pay for flights to go on holiday, even though I am sitting with R12000 worth of Miles, just ???