here is what i would do, just a heads up: go to your friends store and add items to cart, click checkout via paypal. when the site leads you to the checkout page on paypal, write down the email/user id of the paypal seller and notify paypals abuse team, explaining the situation. meanwhile block access to the stores domain until the issue is resolved. if your friend is using remotely hosted downloads, freeze them too. e-junkie support should take care of restoring your friends account when you send them the credentials by email.
