I couldn't redeem my one of my JOI voucher because the place was booked out for 3 weeks till expiry.
But got a refund as soon as I notified JOI via their chat, which took only 1min for someone to help.
I've been told by businesses that the group buy site keep the money from vouchers which don’t get redeemed.
The businesses do not get paid until after the voucher expires.
So for anyone who can't redeem their vouchers due to the business been overbooked should definitely go after the group buy site and demand a refund or complain to fair trading. Such as Scoopon, cause they are solely responsible to provide you a refund if the business can not provide the service.
Good to know. Thanks for sharing this.