Just to point out that despite the ready, and correct, answer from @gavs82008 , we are all just customers here, so you aren’t talking to any Now staffers.
Doesn't mean we don’t know stuff though 😛
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.