Uninstall, reinstall, lost entire vault, how do I get it back

Solution 1:

Your saved data is not synced to your Google account, it is all stored locally on your device. Uninstalling the game will have cleared out all associated data, including your save file.

The only way you would be able to get it back, would be if you had a backup of your device data that you could restore.

Solution 2:

The only way to get your savegame back is if you had your game saved as "cloud Save". If you didn't checked the cloud checkbox (as seen on the image) the savegame is only stored in your phone. So if you unistalled the game, it will be deleted as well.

If you previously saved the game as "Cloud Save", you need to create a new game in the same slot as your previous game was and check the "Cloud Save" option. A popup will come out telling you that there is a conflict and it will ask you if you want to keep the new game or to restore the previous one.