Hi @Anonymous User
A couple of people have reported this recently on the forum.
Here's an example here.
https://community.nowtv.com/t5/Account-Billing/Code-Already-Been-Used/td-p/475584
The only way you can sort this out is to contact live chat (here's a link below to live chat).
Their lines are extremely busy, so just keep trying.
https://help.nowtv.com/contact-us/managing-my-devices
If live chat won't budge or assit you with the voucher code, then take it back to the retailer that you bought if from and ask for either a refund or replacement code.
