The different file types are offered as individual in-app purchases, so you can get just the one you actually need. During the free 14-day trial all premium add-ons are active without any limitation.
Within Letter Opener go to Help > Purchase information to see your in-app purchases.
If you already purchased one or more of the premium add-ons and don’t see them here, you can “Restore Purchases” with your Apple ID.
When you purchase an app through the Mac App Store Apple provides no information to the developer about individual customers or purchases. As a result we have no way of providing refunds directly.
You can get a refund for any app on the Mac App Store by following this process:
Sign In with your Apple ID.
Click “Report a Problem” for the application you want a refund for
- Choose “Problem is not listed here” and be sure to mention that you are asking for a refund because it doesn’t work as expected.