You can use Apple’s Game Center to save, recover and transfer your account to any iOS device. This means that you'll be able to pick up where you left, even if you uninstall the game or switch phones, as long as you use the same account and have a connection to the cloud.
Before you start
Make sure you have Game Center updated. Check for an update at Settings > General > Software Update
Here's a troubleshooting for you to try
Open your game, go to the Options Menu, and check that iCloud save is enabled.
Once Cloud save is on, close the game.
Go BACK and check that you're logged in with the same Game Center account you had used.
- If necessary, change to your desired account at Settings > Accounts > Game Center
Close the game, and open it again!