Changing if a GameObject is active, not working for some parts of the script.

Okay so i'm making a mortal combat sort of game and when I try and set some Gameobjects active off and or on it works. But if I use mainSprite.active = false; (LINE 38 under the input of space), again for the second time it does not turn off the GameObject. Am I doing something wrong? And sorry if i didn't explain more clearly. Also i've tried SetActive and the others.

 var walkSpeed : float = 3f;
 var jumpHeight : float = 2f;
 private var isGrounded : boolean = true;
 var facingRight : boolean = true;
 
 var jumpSprite : GameObject;
 var mainSprite : GameObject;
 var punchSprite : GameObject;
 
 //Player Stats
 public static var bcurHp : int = 100;
 public static var bmaxHp : int = 100;
 public static var bplayerGold : int = 0;
 
 function Start ()
 {
     jumpSprite.active = false;
     mainSprite.active = true;
     punchSprite.active = false;
 }
 
 function Update ()
 {        
     //Movement
     if(Input.GetKey(KeyCode.A)){
         transform.position += Vector3.left * walkSpeed * Time.deltaTime;
         transform.rotation.y = 180;
     }
     
     if(Input.GetKey(KeyCode.D)){
         transform.position += Vector3.right * walkSpeed * Time.deltaTime;
         transform.rotation.y = 0;
     }
     
     if(Input.GetKeyDown(KeyCode.Space)){
         punchSprite.active = true;
         mainSprite.active = false;
     }
     
     if(isGrounded){
         if(Input.GetKeyDown(KeyCode.W)){
             rigidbody2D.AddForce(Vector3.up * jumpHeight);
         }
     }
     
     if(!isGrounded){
         if(Input.GetKeyDown(KeyCode.S)){
             rigidbody2D.gravityScale = 10;
         }
     }
     
     if(transform.position.y > 1){
         isGrounded = false;
         jumpSprite.active = true;
         mainSprite.active = false;
     }
     else{
         isGrounded = true;
         jumpSprite.active = false;
         mainSprite.active = true;
         rigidbody2D.gravityScale = 2.1;
     }
 }