You can use iCloud (iOS) or Google Play Saved Games (Android) to store and restore your existing save data. Simply sign into the account and the save data should be automatically restored.
It is worth noting that signing into any social networking sites such as Facebook or Game Center that have been incorporated into our apps is only to allow scores and achievements to be uploaded, but no actual save data is stored there.
Our older apps - FTS 15, Dream League Soccer - Classic and Score! World Goals do not support iCloud or Google Play Saved Games.