Undersoil is made by one person, and every message gets read. For questions, bug reports, purchase problems or feedback, email:
cburns1993@gmail.com — include your device and roughly when you installed the game, since there are no accounts to look you up by.
Yes. Undersoil is free to play and supported by ads. Some ads are optional and give you a bonus for watching; the only things sold for real money are three gem packs, and everything in the store is bought with gems.
Your progress is saved on your device and backed up anonymously so it can be recovered if the app is reinstalled. There are no accounts, so a save cannot be moved to a different phone. Settings → Erase save data starts you over.
Purchases are handled by Apple or Google and normally arrive within a few seconds. Fully close and reopen the game first, then try Settings → Restore purchases. Still missing? Email the receipt from your App Store or Google Play purchase email and it will be sorted out.
Refunds for in-app purchases are handled by the store: Apple at reportaproblem.apple.com, Google through Google Play's refund page. If something went wrong on the game's side, email first and it will be put right.
The bonus is granted only when the ad reports that it was watched through to the end. If it was and nothing happened, or ads never load at all, send the device, the time it happened and what you were doing, and it will be looked into.
Open Settings in the game and use the Sound, Music and Haptics switches.
See the privacy policy. In the EEA, UK and Switzerland the game asks for consent before requesting any ad and you can change your answer from Settings → Privacy options; on iOS the standard tracking prompt applies.