As you appear to have gone, there seems little point in answering you.
The usual answer though, for the benefit of innocent bystanders, is that you did have an introductory offer (everyone does) and it has expired.
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.
