Melee Damage script by collision

Hi, I'm working on a 2D game and I have been having some problems with melee damage by collision, I made this script:

public class AttackScript : MonoBehaviour {

 public float damage = 50.0F;
 public float attackDuration = 0.3F;
 
 public bool attacking = false;

 
 [HideInInspector]
 
 
 void Start () 
 {
     
 }
 
 void Update()
 {
     
     
     if(Input.GetKeyDown("h")){
         attacking = true;
     }
 }
 
 void OnTriggerEnter (Collider col) 
 {
 
     if(col.tag == "Enemy")
     {
         if(attacking)
         {
             col.SendMessage("receiveDamage", damage ,SendMessageOptions.DontRequireReceiver);
         }
     }
 }
 
 void EnableDamage()
 {
     if (attacking == true) return;
     attacking = true;
     StartCoroutine("DisableDamage");
 }
 
 IEnumerator DisableDamage()
 {
     yield return new WaitForSeconds(attackDuration);
     attacking = false;
 }

}

And the enemy's health script:

public class EnemyHealth : MonoBehaviour {

 public float maxHP = 100.0F;
 public float currentHP;

 public GameObject Enemy;

 // Use this for initialization
 void Start () {
     
     currentHP = maxHP;
 
 }
 
 // Update is called once per frame
 void Update () {
     
     checkStatus();
 
 }
 

public void checkStatus(){

     if(currentHP > maxHP)
         currentHP = maxHP;
     
     if(currentHP < 0)
         currentHP = 0;
     
     if(currentHP == 0)
         death();
 }
 
 public void receiveDamage(float damage){
     
     currentHP -= damage;
     Debug.Log("Damage Applied");
 }
 
 public void death(){        
 
     Destroy(this.gameObject);        
     
 }
 

}

But for some reason it doesn't work, I tried a lot of things and it doesn't work, some help please?