i need your help

im trying to add a sound to my game. when i hit the ball on the groung i should get a sound here is my code in javascript : #pragma strict

 var rotationSpeed = 100;
 var jumpHeight = 8;
 
 var playOnce = true;
 
 var Hit01 : AudioClip;
 
 
 private var isFalling = false;
 function Update () 
 {
     //Handle ball rotation
     var rotation : float= Input.GetAxis ("Horizontal") * rotationSpeed;
     rotation *= Time.deltaTime;
     GetComponent.<Rigidbody>().AddRelativeTorque (Vector3.back * rotation);
     if (Input.GetKeyDown (KeyCode.JoystickButton2) && isFalling == false)
     {
         GetComponent.<Rigidbody>().velocity.y = jumpHeight;
        playOnceTrue();
         }
         isFalling = true;
 }
 function OnCollisionStay ()
 {
 if (playOnce == true);
 {
 var theHit = Random.Range(0,4);
 if (theHit == 0)
 {var audio: AudioSource = GetComponent.<AudioSource>();
     audio.clip = Hit01;
     audio.Play();}
    }
     }
 
     function playOncetrue ()
     {
     yield WaitForSeconds(0.2);
     playOnce = true;
     }
           

im getting a BCE0005: Unknown identifier: 'playOnceTrue' error what should i do ? plzz help