Help ? A glitched trade? He got my items, but I didn't get his!

Ok. So I found a guy who had the 50% 1C golden coupon for sale, I gave him 5 coal and left 4 dead, and he put up the coupon. We both accepted and bam. He has my items, I don't have the coupon. Here is pictures of everything. I'm really fucking pissed because hes avoiding me , so he knows what he did. But the thing is in my trade history it says I received the coupon.

His inventory after the trade (that is my left 4 dead, he must've done something with my coal because I don't see it )

Here is my inventory and my trade history, you can clearly see I got the 1C 50% coupon added, but its not in my inventory.

http://steamcommunity.com/id/gillian_seed

This is his steam ID

Here is mine : http://steamcommunity.com/id/hoopty

I will be submitting this to steam, but need help getting explained what the fuck just happened. Is this a hacked item or something? I obviously didn't get scammed because steam says I received it. I restarted steam and he still has the coupon in his inventory and I don't have it.

And as of posting this his account has been deleted. Fuck.