#1 You got the wrong item.
#2 Return it at your cost, he pays for the right item to be shipped.
#3 If he doesn't agree, inform the appropriate authorities.
#4 Hope warnings are being handed out appropriately in this thread.
Edit: +1 to Illusion, sellers need to know their products, thats basic good business practice. Vlad if i drop by your shop this weekend and ask you something about a BDU set you are selling and you provide me with the wrong information then sorry but you won't be making a sell... Oh and insulting your customer is *never* a good idea... even if the customer is a dipshit