Click on "Return this item" on right of your order on your Purchases page and select "Doesn't match description" as the reason. If necessary escalate it to ebay after 3 complete working days. You will be issued with a paid-for return postage label and your money will be refunded after the item arrives back with the seller.
The seller will also have the option to issue a refund without return but don't close the case before they do. And if they delay be sure to escalate your case within 30 days.