I would suggest check with the manufacturer if the dealer are legit, we have some dealers of famous brands as Sennheiser, Focal, Beyer, AKG, unfortunately no HifiMan, in all these dealers there is no way to listening the phones, so its not easy to get the serial number, to worse they dont stock the top of the line phones at exception of Sennheiser with some HD800 model what were sold by over $3000usd.