Disappearing voucher on FNB

I received a message on my app that i recieved a R1000 superbalist voucher for meeting some criteria. I Redeemed the voucher and saw it in the ebucks voucher section on the app with the code. When I checked a few days later the voucher wasn't there anymore. I called FNB technical support and a guy told me there were some technical fault and that I should wait a few days. FNB please advise what happened to the voucher?