How do you replace Chanel Sunglasses lenses?

I bought a Chanel sunglass on ebay and it has a deep scratch that couldn/t be fixed. How do i go about in replacing the lenses and how much would those cost?|||Only the official Channel store can repair the lenses. Most "fashion" on Ebay are royalty rip offs from Gucci and Tiffany so on so forth. If You got a designer item from Ebay unfortunately w/o a receipt that it's authentic...................it cannot be proven to actually be Channel trademark brand.|||Buy a new one