@Anonymous User
No.
You can test this by putting the device you are watching on into Aeroplane Mode, so nothing gets in or out, and then try watching the download.
Set a Payment PIN on your account so that no-one but you can buy memberships on it. Check your bank accounts monthly for any other unexpected payments to Now. That way you can at least nip them in the bud, while you and Now figure out whose fault they are.