You may freely retrieve your game progress if it has been linked to Facebook, or Google/Game Center (depending on the device you use) whenever you want to!

In order to download your game account, just simply do the following:

1. If you linked your game account to Google or Game Center, add the linked Google/Game Center account in the system settings. If you linked the game account to Facebook, you can proceed right to the next step.
2. Start the game, sign into the corresponding Facebook/Google/Game Center account in the game settings (Settings - Account management) and download your game progress.