Write to support@wayfarer.pics and a human — the one who built the app — will reply.
Wayfarer builds your map from the locations stored in your photos. Photos without location details cannot be placed. Check that your camera saves location (Settings > Privacy & Security > Location Services > Camera), and that Wayfarer has access to your photo library. Photos without a place are not lost — they wait under Lost in the menu, where you can place them yourself.
Open the menu, go to Store, and tap Restore Purchases. Purchases live with your Apple ID, so they come back on any of your phones.
In your phone's photo library, where they always were. Wayfarer reads them in place and uploads nothing. See the privacy policy — it is short and it is honest.