pang clone game issues

Hi,

I am trying to make a pang clone game : bouncing balls you hit them with harpoon like weapon they split into half.

-The walls are bouncy with 0 friction, the balls are rigidbodies.

My issues are:

1-collision between the balls I want them to ignore each others. ---they don't the first time then after the first collision they start ignoring

2-some times the ball get stuck on the y or x axis bouncing -how can I add some multiplier to avoid this issue.

Here is the code:

 var impact : AudioClip;
 var minSpeed:float=5;
 var maxSpeed:float=10;
 var curSpeed:float=0;
 var colSpeedMulti:float=1.1;
 var myball:GameObject;
 
  
 
 function Start () {
 rigidbody.AddRelativeForce(0,-minSpeed,0);
 }
 
 
 function FixedUpdate () {
 
 curSpeed=Vector3.Magnitude(rigidbody.velocity);
 
 if(curSpeed > maxSpeed)
 {
 rigidbody.velocity /= curSpeed / maxSpeed;
 
 }
 
 
 if(curSpeed < minSpeed && curSpeed > 0)
 {
 rigidbody.velocity /= curSpeed / minSpeed;
 
 }
 }

///the collision function: //1-balls need to ignore each others,anything else bounce

 function OnCollisionEnter(col:Collision){
 
 audio.PlayOneShot(impact);
 
 if(col.collider.gameObject.CompareTag("ball")){
 
 Physics.IgnoreCollision(col.collider,collider);
 }
 
 else{
 /// we need some multiplier to avoid getting stuck
 rigidbody.velocity += rigidbody.velocity * colSpeedMulti;
 
 
   
 //score.Score++;
 //lives.currentlives--;
 
 }
 }

// hitting the balls with arrow // if they are not small enough split them otherwise destroy the ball

 function OnTriggerEnter (other : Collider) {
 if(other.gameObject.CompareTag("arrow"))
 {
 
 if(transform.localScale.y!=0.5){
 
 Destroy(other.gameObject);
 Destroy(gameObject);
 
 var ball=Instantiate(myball,transform.Find("span1").transform.position,Quaternion.identity);
 ball.transform.localScale /=2;
 var ball2=Instantiate(myball,transform.Find("span2").transform.position,Quaternion.identity);
 ball2.transform.localScale /=2;
 
 paddle.weaponactive=false;
 }
 else if(transform.localScale.y==0.5){
 
 Destroy(other.gameObject);
 Destroy(gameObject);
 paddle.weaponactive=false;
 }
 }
 }