caution！ dishonest buyer.
He ordered a few of the same items, saying all of them not work.
Sorrry, if one or two have problem,that maybe quality problem,but all of them has problem？ No way.
For this kind of item,sometimes people would ordered wrong item,that would cause the item won't work,they just not realize.
So seller ask this buyer to provides some important and necessarily information to check,this buyer keep avoid giving direct answers. That means he already realized he ordered a wrong item by mistake,but he just don't want to admitt it. He afraid that if he provides the information,that could proof he ordered a wrong item.So he refuse to provide the information seller needs, and open case on seller.

He is very cleaver, for that kind of situation, unless seller can proof he ordered wrong item,otherwise ebay would more likely to stand on his side. Seller would lost money for that order.

For this kind of dishonest,our suggestion is block him. Do not sell to him.
Because he knows very well how to take advantage of you.