Welcome to Salehoo! :)
As with any trademarked products, to get the authentic Dr. Dre Monster Beats headphones you need to get it from the source - Link hidden: Login to view This page has links to authorized online dealers and if you wish to become a reseller it would be best to apply as a distributor directly through their company.
There are a lot of these items from DHGate, but I doubt if they are authentic ones.
Hope this helps. :) Kindly upload a photo when you have the time. :)