UI rotation problem

Hi I have this code to make the button always facing the camera. But I get this weird stretching, and when I use the script on the canvas it does nothing

  Vector3 v = myCamera.transform.position - transform.position;
         v.x = v.z = 0.0f;
         transform.LookAt(myCamera.transform.position - v);
         transform.Rotate(0, 180, 0);