For any questions, issues, or feedback, email aethernalytics@gmail.com. I'll get back to you as soon as I can.
If you've already purchased the unlock and it's not showing, open Still Here, go to Settings, and tap "Restore purchase".
Everything you write is stored on your device. If you delete the app, your entries will be deleted too. If you have iCloud sync enabled, a copy exists in your iCloud account.