You did not send me my Nedbank voucher. I want it/

I used to love this company but not anymore. They disappointed me so much. I redeemed for a Nedbank voucher last month. Now they claim that they send me the voucher but they didn't. They asked for a screen shot and I did sent it. But they still ignore my countless emails. I asked them to check their records then they will see they didn't send me my voucher. I regret choosing a Nedbank voucher. I thought it was going to be send to me by email like Takealot and Checkers. This one is completely different because it work by SMS. Now they refuse to send me my voucher. But deeply I know they also know they didn't send me my voucher. Now I'm wasting my data and time emailing them. I want my voucher enlighten panel.