simply automation and workflow not that simple

One approach would be to instead of publishing/unpublishing content view it a different way. Ubercart + uc_recurring is a great module and you can use roles as well to create a simple subscription system where when your subscription renews (like with authorize ARB) you keep your role, however if you cancel your role is removed and it all ties together. Through your site if you are pulling subscription content you can add a check in your code or views to only show content from the author if the author has a specific role. So in that way you're removing the content without actually having to unpublish it and ubercart handles it for you.

If you still really need to unpublish the content so that it is completely not visible you could create a _cron hook where you use a db query to pull all content from a user that does not have the role he's suppose to have and unpublish it then. It depends on what you're trying to do.

This is complicated enough that you should give up on trying to use rules and create a custom module instead. In fact, this all sounds fairly straightforward to do with some custom programming.

Another way to handle this situation would be to create a "tie-in" module or extra set of code within an existing module that would apply 30-day cookie to the users that have paid for certain content.

with this you may implement hook_init() to test for the cookie on page load and then redirect the user to the content or if they're not a paying customer, to a landing page where they may apply/pay for the content.

the cookie method working along side user roles would be a closer solution to allowing a "real-time" solution for this based on usage statistics.

This would require some custom code to be written but, it would help to avoid the overhead and headache that would be required to get drupal actions or triggers to handle the situation.