I suggest you ring the Broadband support line on the number found in My Account/Broadband & calls/Moving Home (even though you aren’t).
A URL always resolves to an IP address, so an IP address there ought to be acceptable.
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.