Not guaranteed, though nobody has come back lately and said it didn’t work for them.
So please ‘Accept Answer’ now, if you are so inclined, as you won’t be able to come back and do it later
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.