"Pay to Blog" - suspending websites who haven't paid

Hey,
Great plugins guys!

Just a question about Pay to Blog. I'm setting up a multi-site for users to subscribe to the service, to have their own complete Wordpress website.

As it is, if a user doesn't pay their account, they don't have access to the backend until they subscribe again. But I need the frontend website to go down too (as in perhaps it gets redirected to a static - 'This user hasn't paid their account').

How can I do this??

Matt