Can I trigger the check for new orders manually – or from an external script?
WP-Lister uses WordPress internal task planner wp_cron to check eBay for new sales on the set time interval. You can also run this check manually by clicking “Update orders” on the orders page.
WP-Lister for eBay 2.0 adds support for external cron jobs which might be required if wp_cron doesn't work reliably on your site - or if you're using WP-Lister for Amazon as well, in which case you shouldn't rely on your site's traffic to trigger wp_cron.
We are also working on using the eBay Platform Notification system to get instant notification on any sale, but this will take some more time. As eBay states in their own API documentation, platform notifications are not considered “reliable”, so every application that uses them should frequently check for new orders anyway.