Facebook, Twitter, and Google Login

Hello,

I recently installed and configured the plugin. Everything appears to be working fine. However I have a question.

When users utilise their social media accounts to make a purchase.
"Let users create accounts with Twitter, Facebook and Google +. No need for visitors to create an account with you... makes payment super easy.")

How do they regain access to the content they paid for via pay per view or a subscription when they return/ have been logged out/ use a different machine?