Reverser kit! (Based off of switcher)

I am making a kit called Reverser. Its a remake of the kit switcher. For what ever reason, this code is not working and I am confused why it wont. It is probably a real simple fix but I need a 2nd pair of eyes to help me.
(Reverser - throw a snowball at your enemy to switch places!)

Code:java

 public void onReverser(EntityDamageByEntityEvent e){
 
if (e.getEntity() instanceof Player && e.getDamager() instanceof Snowball){
 
Player p = (Player) e.getEntity();
Snowball s = (Snowball) e.getDamager();
Player shooter = (Player) s.getShooter();
Location ShooterLoc = (Location) shooter.getLocation();
if (!plugin.Reverser.contains(shooter.getName())){
if (shooter.getItemInHand() == new ItemStack(Material.SNOW_BALL)){
p.teleport((org.bukkit.Location) ShooterLoc);
shooter.teleport(p);
}
}
}
}
}
 

 

Code:java

if (!plugin.Reverser.contains(shooter.getName())){
 

You are checking if it doesn't, and if it doesn't, then it switches their locations.