If you're experiencing purchase-related issues, such as your paid items not showing up, you may be using an outdated version of the launcher.
Please try playing the game through the store and updating your launcher to the latest version to see if those resolve the issue.
If the above does not resolve the issue, please try re-installing Google Play Games to see if it solves the problem.
*To get the latest launcher from the store, please link your Sonic Rumble account first, and then uninstall and reinstall both the app and the launcher.
If the issue persists, please contact Google Support using the following link:
https://support.google.com/