If youd sell something that the buyer complain about faulty, ebay will never ask buyers for evidence, if you as seller will ask buyers for evidence, ebay don't consider that. If different item returned or item opened and parts charged, you'd open case against to buyer and eBay wouldn't give a damn, eBay will refund straight away saying WE REFUNDED TO BUYER BECAUSE ITEM SUCCESSFULLY RETURNED. I'll never sell again on eBay.