@Lyns
Look at the Now account details on your phone, and then double-check that you are logged in with the exact same details on your TV.
Account details are either under a little head and shoulders icon at the top, or to be found in the very bottom right thumbnail, on your Now Home screen.
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.
