Code not working

I'm making my first pocketmine plugin but doesn't work, please tell me what I did wrong, thanks.

PHP:

<?php

namespace KillCheck;

use pocketmine\utils\TextFormat;
use pocketmine\command\CommandSender;
use pocketmine\plugin\PluginBase;
use pocketmine\utils\Config;
use pocketmine\Player;
use pocketmine\server;
use pocketmine\level;
use pocketmine\item\Item;
use pocketmine\event\Listener;
use pocketmine\command\Command;
use pocketmine\event\block\BlockPlaceEvent;
use pocketmine\event\player\PlayerDeathEvent;
use pocketmine\math\Vector3;
use onebone\economyapi\EconomyAPI;
use pocketmine\event\entity\EntityDamageByEntityEvent;
use pocketmine\event\entity\EntityDamageEvent;

    class Main extends PluginBase{
/*******************************************************************************************************/
       
        public function onEnable(){
            $this->saveDefaultConfig();
            $this->reloadConfig();
            $v = "0.1";
            $c = "Artide";
            $this->getServer()->getPluginManager()->registerEvents($this,$this);
            $this->player = EconomyAPI::getInstance();
            $this->getLogger()->info("Plugin loaded! v_".$v." By ".$c);
        }
/*******************************************************************************************************/
   
        public function onPlayerDeathEvent(PlayerDeathEvent $event){
            $player = $event->getEntity();
            $name = strtolower($player->getName());
            if($player instanceof Player){
                $cause = $player->getLastDamageCause();
                if($cause instanceof EntityDamageByEntityEvent){
                    $killer = $cause->getDamager();
                    if($killer instanceof Player){
                        $killer->sendMessage($this->getConfig()->get("Killer-Message"));
                          $this->player->addMoney($killer, $this->getConfig()->get("Added-Coins"));
                            if($this->getConfig()-get("Disable-Killer-Coins") === true){
                               $this->player->addMoney($killer, 0);
                                $player->sendMessage($this->getConfig()->get("Player-Message"));
                                  $this->player->reduceMoney($player, $this->getConfig()->get("Reduced-Coins"));
                             if($this->getConfig()->get("Disable-Coin-Reduction") === true){
                                $this->player->reduceMoney($player, 0);
                return true;
               
        }else{
          return true;

            }

         }
                
      }
      
    }
       
  }
   
}
/*******************************************************************************************************/
       
        public function onDisable(){
            $this->getLogger()->info("Plugin unloaded!");
        }
       
}
?>

What is the error? Does a part of it not run? Does it crash the server entirely?

Nothing happened, it just disabled for nothing...

The opposite of that

You must implement the PocketMine Listener interface

I already corrected it, I'm waiting for the approval to update it. Here's the souce code: https://github.com/Artide/PocketMine-Plugins/tree/master/KillCheck