We're really sorry to hear that, we completely understand how frustrating it can be to lose progress. Unfortunately, there is no way for us to retrieve lost data as everything is stored in the cloud by Google or Apple directly.

When reinstalling the game or installing it on another device, it is necessary to make sure that you are connected to your cloud account in-game and wait until the synchronization is complete before playing.

Regarding how checkpoints work in-game, please check this article.