Scammed When Buying Virtual Items

[nicksonlinecardshop]

So recently I bought a knife for the first person shooter game CS:GO.  This is a virtual item that you can use to play in game.  I negociated with the seller and once we came to the deal of $250 CAD or $202.67 USD, he told me to send him my Steam Trade Link.  The Steam Trade Link allows the seller to send the knife to my account in a trade offer that I have to accept.  After the purchase the buyer constantly went repeating replies from older messages telling me about the knife, saying he posted it, and to send him the money direct on PayPal because he said it would charge him to go through eBay (take note this is after the payment was accepted).  I have been trying to get in contact with him for the past few days and he keeps saying he sent it and I had appeared to accept the offer.  I have sent him lots of proof showing that I never got an offer and very specifics to which one was my account just incase he sent to the wrong one.  Now, I cannot get any contact from the buyer and I can't do anything.  Please Help!  Thanks!

Item Link:

http://www.ebay.com/itm/CS-GO-Karambit-Blue-Steel-Minimal-Wear-/252038737126?ssPageName=STRK%3AMEBID...

I just found the ebay picture on this website: 

http://www.sythe.org/steam-sales/1683311-karamabit-blue-steel.html