List.contains doesn't work and add duplicates

I am trying to avoid having to add duplicates in a list but for some reason the code doesn't work. What am I doing wrong? here is the code:

  CharacterController characterController = GameObject.Find("Player").GetComponent<CharacterController>();
         Vector3 pointOfOrigin = transform.position + characterController.center;
         RaycastHit[] hit = Physics.SphereCastAll(pointOfOrigin, characterController.height / 2, transform.forward, 0.5f);
 
         List<int> enemiesHit = new List<int>();
         
         for (int i = 0; i < hit.Length; i++)
         {
             if (hit[i].transform.gameObject.tag == "Enemy" & !enemiesHit.Contains(hit[i].transform.gameObject.GetInstanceID()))
             {          
                 enemiesHit.Add(hit[i].transform.gameObject.GetInstanceID());
                 hit[i].transform.gameObject.GetComponent<HealthController>().TakeDamage(damage);
             }
         }
 
         for (int x = 0; x < enemiesHit.Count; x++)
         {
             Debug.Log(enemiesHit[x]);
         }