This is a professional trouble maker. Be careful. Sometime seller would make mistake on listing,that happens,but this guy is search and aiming the listing that has mistake,all seller did not explain the item clearly on the listing. He will directly reports to eBay that the seller is a fraud or deception. Than he will contact seller, tell seller to pay money to him,otherwise he will keep reporting,and make us a lot of story saying the seller is fraud,to make the seller reputation looks bad.

Do not pay any money to him,if your listing has mistake,change it immediately is enough.
And block this buyer,don't let him buy problem you,because you will have more trouble if you let him actually pay the order.