You must select "Privacy Controls" in the Settings menu. In this screen, you should select "Remove Data". This will submit a request to delete your data from the MAG servers.
Your data will be deleted for all MAG Games and cannot be localised to a specific MAG game.
The process takes 14 days to complete in which time you can cancel the deletion request.
Once you have requested the deletion of your data, you can also delete all of our Games from your device. To ensure your data is not registered to the server again, you must also delete the Games from your device.