1. Please make sure you download the game through the official app markets Google Play Store or Apple App Store. If you download the game through unofficial sources or other app markets, critical issues or security problems can occur and and it's possible that the game cannot be updated properly.
2. (For Android only) Please refresh the Google Play application’s app data. Follow these steps – Setting – Application manager – Google play store – Clear data. (The exact names of the settings may be different, depending on the Android version.)