Load score

I have created a fastest time table and i have written a script with saves the current fastest times to a .txt file. I have then written this code to then be able to load that file and put the saved times back on the board but when i click the button to activate it the code doesnt seem to work? Can anyone please help me.

 using UnityEngine;
 using System.Collections;
 using System;
 using System.Runtime.Serialization.Formatters.Binary;
 using System.IO;
 using System.Collections.Generic;
 
 
 public class LoadScore : MonoBehaviour 
 {
     public GameObject Firstt;
     public GameObject Secondd;
     public GameObject Thirdd;
     public Color magic;
 
     void OnMouseEnter()
     {
         GetComponent<TextMesh> ().color = Color.red;
     }
     
     void OnMouseExit()
     {
         GetComponent<TextMesh> ().color = Color.white;
     }
 
 
     void OnMouseOver()
     {
         if (Input.GetKeyDown(KeyCode.Mouse0))
         {
             string readtext = File.ReadAllText(Application.dataPath + "/RunHighscores.txt");
             string first = readtext.Substring (8,3);
             string second = readtext.Substring (22,3);
             string third = readtext.Substring (35,3);
 
             int First = int.Parse(first);
             int Second = int.Parse (second);
             int Third = int.Parse (third);
 
             PlayerPrefs.SetInt ("First", First);
             PlayerPrefs.SetInt ("Second", Second);
             PlayerPrefs.SetInt ("Third", Third);
 
             Firstt.GetComponent<TextMesh>().text= "1ST PLACE - " + First;
             Secondd.GetComponent<TextMesh>().text= "2ND PLACE - " + Second;
             Thirdd.GetComponent<TextMesh>().text= "3RD PLACE - " + Third;
 
 
         }
     }
 
 }