Hi @Anonymous User
Sorry to hear that your getting charged.
If you check My Account > My Passes or My Account > View My Bills and they don't show any active passes or recent transactions then your payment details must be located on another NOW TV Account.
Can you check any other usernames that you may have set NOW TV up on including any that you may have used with another Sky service, may also be worth checking with any other members of the household who have access to your payment card to see if they have setup a NOW TV Account using your details.
If you have checked all of the above and have no joy then the next step would be to speak with your card issuer as your card may have been used without your permission to setup a NOW TV Account.