Board Thread:Game Discussion/@comment-31.22.50.5-20171005202326/@comment-28169398-20171005215921

The game automatically does a cloud backup every 12 hours, if you are using it online (WiFi or Cellular). Try going to the Cloud Save/Restore in settings and try restoring your device. That screen should tell you the time of your last backup.

Another option is to Restore a backup of your whole device, if you have made one recently. On iOS, you would perform this in iTunes.