Write to ritambuj@gmail.com. A real person reads it. Say which phone you have and what happened, and you will get a reply.
Progress lives on the device, so uninstalling the app or clearing its storage removes it, and it cannot be brought back. Signing in to Play Games keeps your leaderboard totals with your Google account, which is the one part that survives a reinstall.
Make sure the Google Play Games app is installed and you are signed in to it. If the game was installed from somewhere other than Google Play, sign-in will not work — the build has to be signed with the key the store uses.
Pinch to zoom in; the board pans and zooms freely. The recentre button in the top bar frames the whole board again. Later levels are forty cells across, so zooming in is the expected way to play them.
Two snakes moving at once can meet in a cell that looked empty when you tapped. If you see a collision you cannot explain, send a screenshot — that is exactly the kind of report worth having.
The speaker button in the top bar mutes everything, including haptics.
What helps most: the level number, what you tapped, what you expected, and what happened instead. A screenshot or a short screen recording is better than any description.