@TraLaLaLaLa they will have a card on file, they probably forgotten that they did it.
To avoid being charged just cancel your passes once applied, then at worst you'll have no service for a day until you get a new voucher.
This is a community forum so account matters can't be handled here.
Here are some helpful details http://help.nowtv.com/article/How-to-cancel-NOW-TV
You may need LIVE CHAT which you can reach via contact us - blue box bottom left