Vouchers not working

The Rosebank Kauai has refused to accept my Rewards Voucher on two occasions. The first time they claimed the system to be offline only after I gave them my voucher, luckily the staff didnt use it before I could. The second time happened this morning, they claimed my voucher is \invalid\". Please explain to me how this is even possible. I claimed my reward and added it to my Apple wallet exactly like any other day. They then look at me like I'm claiming a false voucher or like its my fault their systems arent working. Please address this."