Mp7 bug

Congratz z8games ! after 1 week, now i can play crossfire.
But there is one for error.
Yesterday i bought 45 crates, i won 7 mp7s , no thompsons.
I tried to sell 6 of them
But it said Fail to .... (something i don't remember)
and my 6 mp7s dissappear after i log in back!
Anyone has the same problem?
I sent 2 tickets today and no reply from z8games