@Anonymous User as per the numerous replies above, if clicking on My Account takes you to the NOW TV homepage you have used the wrong username. Yes the details you enter let you view the site and read the forums, but this isn't the username you signed up with and which has your card details against.
Once you get the correct username (try checking the device you use, your username should appear when loading or in the settings, or hunt through your emails as the username often appears on the marketing emails) you can cancel with a few clicks.
