In your order history, I see you had the Annual Subscription, and them upgraded to Super Suite. The Digital file pro 2 serial number would be from the annual subscription, which was discontinued over 2 years ago.
When you upgraded to Supper Suite, we had released the upgrade to Universal Email 4 that included the Digital File Pro functionality.
You should uninstall Digital File pro, and then install Universal Email 4, that will give you the functionality of Digital File Pro.