To ensure you can retrieve a saved game, it must first be linked to Facebook prior to

Using a new device
Reinstalling the app
Resetting a device to factory defaults

Retrieve the save by clicking on the gear icon in game. This brings up the "Settings Menu". From there tap on "Account Info" and enter the Facebook login information to retrieve the saved game.
 
If you encounter an error while logging into your Facebook account in-game, please see Why can't I load my Facebook connected save?

If you are still having issues with this please feel free to reach out to us at hphm-help@jamcity.com. We will be happy to help!