How to load best score from leaderboard

I am using Git-hub plugin for leader-board.I have successfully posted score but now i have to get best score from leader-board to show in game-play. I am using this code but it shows nothing.Please guide me.

 ILeaderboard leaderboard;
 leaderboard = Social.CreateLeaderboard();
 leaderboard.id = "CgkIlOyC3sIDEAIQAA";
 eaderboard.LoadScores (result => {                
                 Debug.Log("Received " + leaderboard.scores.Length + " scores");
                 foreach (IScore score in leaderboard.scores)
 
                     myScores=score.formattedValue;
                     Debug.Log(myScores);
             });