My ball in pong passes through the paddles.

I'm trying to make a pong duplicate and the ball keeps passing through the paddles. It's slow enough to see go through the paddle. Here is the Ball Movement Script.

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

public class BallMovement : MonoBehaviour {

 public float speed = 10;

 private Rigidbody2D rigidBody;

 //private AudioSource audiosource;

 void Start () {
     rigidBody = GetComponent<Rigidbody2D>();
     rigidBody.velocity = Vector2.right * speed;
 }

 void OnCollisionEnter2D(Collision2D col)
     {
     if ((col.gameObject.name == "Left Paddle") ||
     (col.gameObject.name == "Right Paddle"))
     {
         HandlePaddleHit(col);
     }
     if ((col.gameObject.name == "Wall Top") ||
     (col.gameObject.name == "Wall Bottom"))
     {
         //SoundManager.Instance.PlayOneShot
         //(SoundManager.Instance.wallBloop)
     }
     if ((col.gameObject.name == "Right Goal") ||
     (col.gameObject.name == "Left Goal"))
     {
         //SoundManager.Instance.PlayOneShot
         //(SoundManager.Instance.goalBloop)

         transform.position = new Vector2(0, 0);
     }
 }

 void HandlePaddleHit(Collision2D col)
 {
     float y = BallHitPaddleWhere(transform.position,
         col.transform.position,
         col.collider.bounds.size.y);

     Vector2 dir = new Vector2();

     if(col.gameObject.name == "LeftPaddle")
     {
         dir = new Vector2(1, y).normalized;
     }
     if (col.gameObject.name == "RightPaddle")
     {
         dir = new Vector2(-1, y).normalized;
     }

     rigidBody.velocity = dir * speed;

     //SoundManager.Instance.PlayOneShot
     //(SoundManager.Instance.hitPaddleBloop)
 }

 float BallHitPaddleWhere(Vector2 ball, Vector2 paddle, float paddleHeight)
 {
     return (ball.y - paddle.y) / paddleHeight;
 }

}

If able, please tell me anything wrong with the code.