Email us. It reaches a person, not a ticket queue, and there is no account to log into and no form to fill in.
None of this is required, but each one saves a round trip:
Cornered has no accounts and no server holding your history, so we cannot look your game up or restore it for you. Settings has an Export that writes a file you keep, and that file is the thing to send if a board looks wrong. Deleting the app deletes everything with it.
Anything you buy is handled entirely by Apple or Google. We never see your card and cannot reverse a charge, so refunds go through them: Report a Problem in your Apple purchase history, or the order history in Google Play. If a store turns you down and you believe it was our fault, write anyway and we will see what we can do.
This is a small company and support is answered by a person between other work, so expect a few days rather than an hour. If something is badly broken for a lot of people, the fix usually arrives before every email is answered.