Fake items

[Feed Me]

so, i traded a few items for 2 crates. then i was trading those 2 crates with razor1 and it gave me an error saying "The trade was cancelled because some items do not belong to you or the other player." so then i thought it was just a common error, then i traded with matt, and it gave me the same error...
submitted a steam support ticket but it takes ages for them to get answered
can anyone help me? 3:

 

[Bonecrusher]

1) When you traded and you got that error, were the items still at you or they were gone?
2) Did you try to exit game>steam then get in game again and trade?
3) Did you trade later? Did the same error happen again?

 

[Feed Me]

1) When you traded and you got that error, were the items still at you or they were gone?
2) Did you try to exit game>steam then get in game again and trade?
3) Did you trade later? Did the same error happen again?

the crate disappeared when i restarted tf2 and my item that i traded for the crate was gone :l