Not sure when it expires but I just used my $20 amazon voucher and there were a lot of hoops to jump through (new user, over $79, and amazon au had to be the seller).
Saw that I have an escape room voucher expiring in March so have to use that soon and figured others could do with a reminder.
Also, check that the links to your vouchers actually still work. I had two vouchers, which expired in March (car wash, melb aquarium), and the link was dead. Had to email them to get them to send it to me. Took about a week to get sorted