Remove the item drop, don't just cancel the event

Plugins/mineplex-game-gemhunters/src/mineplex/gemhunters/loot/LootModule.java

@@ -546,6 +546,7 @@ public class LootModule extends MiniPlugin
 		for (LootItemReward storedReward : _itemRewards) {
 			if (storedReward.getItemStack().isSimilar(dropped)) {
 				event.setCancelled(true);
+				event.getItemDrop().remove();
 				event.getPlayer().sendMessage(F.main(_moduleName, "You can't drop special items in Safezones."));
 				return;
 			}