It is important to note, Relcozsh, that the term "ninja" does not generally apply. You are simply unable to loot an item that you do not qualify for within the World of Warcraft.
Now if you believe that a scam took place, please submit an in-game petition and report it. Our In-Game Support staff will look into your report and take appropriate actions based on what was found. More information on our scam policies can be found in the following Support Article.