Pong game collision problems

Hi and frist of all thank you in advance for yout time and sorry for mu english.

Well i just finished my frist game a simple pong clone.

Link to game: http://fdeluna.itch.io/pong-clone

I have two problems,

1º when the ball collide with the up or down wall in a close angle, the ball doesn´t bounce it just get stick to the wall and just stoped.

2º when the balls collide i create particules from a prefab. the problem is that the particules spam in the collision position and in the prefabs position and i dont know to solve this.

Code where i calculate the direcction of the ball and code where i update the direction of the ball

 void FixedUpdate () {
         transform.position += gameLogic.ballDirecction * gameLogic.speed;
 }

 void OnCollisionEnter(Collision collision)
     {
         ContactPoint contact = collision.contacts[0];
         Vector3 normal = contact.normal;
         gameLogic.ballDirecction = Vector3.Reflect(gameLogic.ballDirecction, normal);
 
         Instantiate(Instantiate(Resources.Load("particle_collision")),contact.point,Quaternion.identity);
     }

PS: the code are in differents scrips.

thank you very much.