When did you take the membership out? There are no free trials anymore with the entertainment or cinema memberships, so payment is taken straight away.
For any chance of a refund you must speak with staff via live chat. By clicking "chat online" within the green box, make sure to avoid "get help quicker" as this is a bot.
How To Submit A Complaint (nowtv.com)
FYI that I do not work for NOW, just a NOW customer trying to help