Variable bug???

// my variable named NumberOfButtons print 1 + 1 + 1 every 2 seconds due to my invokerepeating but when I clic on one of my circles it does not do a - 1 on the variable it keeps going + 1 + 1 + 1 + 1 when it should do + 1 -1 + 1 + 1 + 1

using System.Collections; using System.Collections.Generic; using UnityEngine;

public class TheGame : MonoBehaviour { public Texture2D NormalCursor; public Vector2 hotspot = Vector2.zero; public CursorMode cursormode = CursorMode.Auto; public float GameBegin = 0; public GameObject Button; public float NumberOfButtons = 0; //buttons are the dot the player will have to clic public float Spawning = 0; public float Spawnn = 0;

 private void Start()
 {
     Cursor.SetCursor(NormalCursor, hotspot, cursormode);
 }

 void Update()
 {
     if (GameBegin == 0)
     {
         NumberOfButtons = 0;
         Spawnn = 0;
         if (Input.GetKeyDown(KeyCode.E))
         {
             Spawning = 1;
             Spawnn = 1;
             if (Spawning == 1)
             {
                 InvokeRepeating("Spawn", 2.0f, 2.0f);
                 Spawnn = 1;
             }
             print("A New Game Has Begun");
             GameBegin = 1;
         }
     }

     if (GameBegin == 1)
     {
         if (NumberOfButtons >= 7)
         {
             Spawning = 0;
             print("GameOver");
             GameBegin = 0;
             //var ButtonClone = GameObject.Find("Button (Player)(Clone)"); //repair
             //Destroy(ButtonClone); // repair
             print("Game Has Restarted" + " " + "Press E To Continue");
         }
     }
 }

 void Spawn()
 {
     if (Spawnn == 1)
     {
         var position1 = new Vector3(Random.Range(-8.30f, 8.30f), Random.Range(-3.50f, 3.50f), 0f);
         Instantiate(Button, position1, Quaternion.identity);
         NumberOfButtons = NumberOfButtons + 1;
         print(NumberOfButtons); //for testing purpose
     }
 }

 void OnMouseUp()
 {
     NumberOfButtons = NumberOfButtons - 1;
     print(NumberOfButtons);
     Destroy(this.gameObject);
 }

}