Protea Hotels Prokard System

I've been told that I can contact you with regards to the Protea hotel prokard membership complaint I have. <br> <br> I have been trying to book at different protea hotels around the country using my prokard vouchers, but most of the times when I try to make a booking I'm being told that they are fully booked but when I book without using a voucher then there is availability. This happens regardless of how far in advance I try to book. I've tried to make my bookings in such a way that they don't fall on long weekends, school holidays, or events weekend but 95% of the time I don't get to use that voucher. I am now very fed up and very disgusted with this prokard membership system. When I signed up and paid membership fees I was not told of this nonsense. Why give me vouchers if you wont let me use them?