My Enemies start to shoot wrong way.,Help me my enemy's dont shoot at me

I'm adding 1 enemy and start shoots at me its fine but i add 2 or more enemies my enemies starts shooting randomly. I think my character's position dont updating I'm new at Unity please help me...

public Vector2 getYon() {return (karakter.transform.position - transform.position).normalized;}

 void Start()
 {
     dusman = GameObject.FindGameObjectWithTag("dusman").GetComponent<dusmanKontrol>();
     fizik = GetComponent<Rigidbody2D>();
     fizik.AddForce(dusman.getYon() * 1000);
 }