Scamming topic!

guys recently our apprentice mits claim that hes beed scammed by Angelofdeath. Well he said that he got an unfair trade for his first found gem which took him 4 months to find. He traded his zoisite for 2 zoas and 1 griffin cape, then he tell mits to trade griffin for zoa again and in the end didnt trade the zoa back. so guys i would like to hear your opinions regarding the matter, especially Angelofdeath and what should be done to prevent this happening, as for all we know, history repeats itself........