Static var works in Unity but not on mobile device

Hey, i have a static int variable to save score and highscore and display in several scenes. It works just fine in Unity but in the finished Build both variables arent working. Any Suggestions how to fix it?

The Score Script

public class ScoreScript : MonoBehaviour {
public float pipeFrq;
public static int Score = 0;
public static int Highscore;
public Text countText;
public AudioSource Scoresound;

void Start () {


	InvokeRepeating ("CreateScore", 3.9f * pipeFrq, pipeFrq);
	countText.text = "0" ;
	Score = 0;
	//countText.text = Score.ToString ();

}

void CreateScore(){
	
	Score = Score + 1;
	countText.text = Score.ToString ();
	Scoresound.Play ();
	if (Highscore < Score) {
		
		Highscore = Score;
		PlayerPrefs.SetInt ("Highscore",Highscore);
		PlayerPrefs.Save();
		
		
	}
	
	
	
}

}

For the GameOver Scene

public class GameOverScript : MonoBehaviour {

public Text scoreText;
public Text highText;
public int Score = ScoreScript.Score;
public int Highscore = ScoreScript.Highscore;

// Use this for initialization
void Start () {
	scoreText.text = Score.ToString ();
	highText.text = Highscore.ToString ();


}

It is working in the unity engine but not on a mobile device of choice

Try to use PlayerPrefs

highText.text = PlayerPrefs.GetInt("Highscore").ToString();