1. AVOID listings which specify that the item has no packaging. This is an almost sure-shot sign of counterfeits
2. CHECK the photo and description carefully. For instance, the MDR-NX1 is a neck-strap style set of headphones. If the earphones look as though they have no neck strap like in figure A, or you are dubious about anything, ask the seller. I won't name names, but the listing with figure A as its snapshot specifies ‘MDR-NX1’ and ‘neck-strap style’. The picture shows no neck strap in the packaging. Upon asking the seller if it has a neck strap, he replies that it doesn't.
4. If you receive fakes then there is still hope. First of all, write a polite but firm message to the seller, telling them that the headphones you received are definitely not MDR-NX1's or MDR-EX71SL's like the listing described. ‘I have seen the headphones before, and these headphones do not have the usual neck-strap’ or ‘do not have a pinhole diaphragm, the sound quality is poor’. If you feel it's necessary, attach some pictures of your counterfeit headphones and point out what's wrong with them. End the message asking that the seller replies soon to tell you what they plan to do to rectify this mistake. Try: ‘please contact me as soon as possible with details on how you plan to rectify this mistake’. The message you have to get across is that the item is not Sony, so the item is not as they described it, so they are the ones at fault, and should refund you or whatever. The seller may pay for the return postage or let you keep the crappy headphones if they feel their feedback is at risk, but don't threaten them outright.