I get what you are asking for, and why, but:-
on what TV guide?
why not all Freeview channels?
Freeview Stream, as I call it, the provision of all Freeview channels over the internet, is a pipe dream of mine that I hope is going to come true.
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.