It always happens to us at least once before we are able to tell a scam from an actual deal. Just be more cautious next time. More times than not, you won't get anything unless you are offering something in game that is worth WAY more than that upgrade like private warps or 100's of thousands of dollars.Scamming in-game items/money for promises of ranks/keys/etc. are allowed. If you were scammed and you suffered a real-life financial loss, then you may report the player with sufficient evidence.