If the buyer already sent them back, I'm not sure what fighting it will do.
While some of the "authenticate this" brands require active listings, others will authenticate from pictures as long as you aren't thought to be promoting your item. And the "authenticate-those-shoes" sub is one that will help you.@BeenBurned thanks for replying however my shoes werent sold through an ebay listing. It was done as a paypal transaction but not actually sold through ebay so i dont have a listing.