I did not receive the voucher that I won

On the 7th of July I Won R1000 shopping voucher till to date never recieved my voucher.When I'm emailing them they tell me about the voucher that I won in April while I'm asking about the one I won in July. On the other email they said my voucher was sent few weeks back and there's no sms I recieved and there's zero balance on my tuyu wallet. I'm so disappointed on them the way I've been doing surveys using my data and time I'm so annoyed