Have made ingame reports about this too but no responses.
Here is the thing:
Over a week ago or so I bought a lvl 27 cloth "of the owl" head piece from the AH for 40s. Since I'm not lvl 27 yet I left it in the mailbox (to save space in my bank). Then a couple of days ago I logged in and noticed that there were now 2 mails in my mailbox with this head piece in it. The original from the AH plus a mail with a very long number as subject. I was confused so just to be sure I decided to take the head piece out of the mailbox. When I took the one that came in new, the one in the original mail also disappeared.
I admit, I hoped I would have had the head piece twice there, but now I had 1, as it should be. So I put the head piece in the bank and did not think about it again. Until yesterday when I noticed an empty spot in the middle of my bank slots, where my head piece used to be. It vanished.
So in conclusion, I would like that head piece back please.