I didnt create this just supporting the creator so they can keep updating it
http://wordpress.org/extend/plugins/wp-zombaio/
his Plugin allows Site Admins to easily configure and use the Adult Payment Gateway Zombaio for use with WordPress. In a more Secure and WordPress-y way that the existing recommended script.
Two ShortCodes help to make joining the site and displaying the Zombaio Site seal as easy as possible. As well as logging transmitted data from Zombaio as a Custom Post Type.
Currently only User Add, User Delete and User Rebill are Processed. But all data is logged.
In the future, Credit Purchase will be supported.
When a user delete/cancel occurs, the admin can choose whether the User is deleted from WordPress or just suspended from being able to login.
This plugin works with "Anyone can register" disabled, stopping users signing up without using a Zombaio based Join Form.
Built in Splash Page/redirection allows you to redirect logged out users to a WordPress Page of your Choosing, thus protecting your content from non members, as well as giving you the ability to warn users about the site content, or create a suitable "Join my Site" page.