Bouncy on player not working

When my player collides with an tagged object my player isn't being pushed forwards, it just constantly freezes the positions (X &Y) and the rotation in the Rigidbody (which I already know). Do I need to add or increase the drag in the Rigidbody or change my tags or something that I'm missing? Can someone help?

  public class PlayerController : MonoBehaviour {

  public float force = 10f;

   float speed = 5f;
   float freezeTime = 1f;

    bool isCollide = false;
  
    void FixedUpdate () 
    {
    float dirX = Input.GetAxis ("Horizontal");
    float dirY = Input.GetAxis ("Vertical");

    Vector3 movement = new Vector2 (dirX, dirY);

    if(isCollide==false)
      GetComponent<Rigidbody2D> ().velocity = movement * speed;
     }

        void OnTriggerEnter2D(Collider2D other)
      {
      if (other.tag == "Boundary") {
        isCollide = true;
       GetComponent<Rigidbody2D> ().AddForce (-GetComponent<Rigidbody2D> ().velocity * force, ForceMode2D.Impulse);
       Invoke("StartFreeze", 0.1f);

      }
 }

  void StartFreeze()
  {
  GetComponent<Rigidbody2D> ().constraints = RigidbodyConstraints2D.FreezeAll;
   Invoke("ExitFreeze", freezeTime);
   }

   void ExitFreeze()
    {
    GetComponent<Rigidbody2D> ().constraints = RigidbodyConstraints2D.None;
    isCollide = false;
     }
  }