If you send a email to support@highexp.eu they might help you recover it. But you need a legit reason.
E.g if you sold it for your benefit, I doubt they will help you
How much cost the green diamon? i loose my diamond cause i was transferring my green diamond to mi knight and a player i dont know who use bot and putc cc and gp in my depot and i cant move the money and i loose my diamond cause map clean