how to disable user accounts who do not pay

We are having a lot of users create an account and then not complete the payment process. This leaves users with accounts without any subscription. This is something we do not want them to do. (it's confusing the end user and creating a lot of support emails)

I found this article which is what we are looking for, however that option is no longer on the Membership -> Options page. Did it move? Is there a different way to prevent this from happing? Please help.