Expand South Africa facebook competition

This has to do with the recent competition going on by Expand South Africa on facebook. I feel cheated. I played and won a couple of times they haven't sent my winnings and they have been ignoring my inboxes and emails. Another thing is I feel like this game we are cheated. We answer within seconds but sometimes our names don't show up on the board even when we sent correct answers. Why start a competition when you can't fulfill your promises. Some of us try hard and make data advances just so we can play this game because we are in need of the money. It's really sad honestly. I'm a Nedbank customer but I'm so disappointed!!!