No seller can guarantee that all products will not have problem，if unfortunately you got a item that has problem，you can contact seller，they will try our best to help you，if the problem still cannot be solved，they have no problem to let you sent it back for replacement or refund.
He said he wants refund
Seller have been try best to help him, even willing to pay the return shipping fee to let him send back, but seller end up receive a negative feedback (full with lies) and a Received an email with sarcasm and teasing tone.

He wants seller to full refund him but not having the item back. So we think the seller's item has no problem,this buyer is a scammer,he just want to get the item for free. So get the money back but still have the items,that means he gets the item for free.

So,we suggest all seller block this guy.