If you've lost your progress, we recommend you to take these steps:

1. Check your network connection. You should be connected to the network.
2. Check if you're logged into Google Play Games (via Settings -> Google -> Google Play Games). We can't restore the progress if you weren't logged in Google Play Games before you've lost it.
3. Run the game. The game will prompt you to login into your Google Play Games account. In case that didn't happen, press the SETTINGS button in the drop-down menu and press the 'CONNECT' button on the right.

If the mentioned above steps didn't help you, please contact us directly.