Want my 300 rand back

I so disappointed in the rewards as they only offer a minimum of food vouchers , most of the things we don't even use. I have not used any vouchers or received my sim card. So why keep my 300 rand. I cancelled but they refuse to refund my money. Nothing has been received or used from them Its disgusting that they actually keep your money.....its a damn ****....don't use them..be careful out there. ..