I received emails offering now sky sports for £19.99
i tried to sign up all day yesterday and always got a technical error message today voucher expired. Not a very honourable company.
Have you tried another browser I take it?
Worst case jump onto live chat and speak with staff who should be able to sort it for you. Just make sure you click "chat online" and not "get help quicker" as the latter is a bot.
https://help.nowtv.com/article/how-to-submit-a-complaint