I need to return one of mine too. I bought one from AZ and one from Newegg and since they don't have serial numbers I can't differentiate between which is which. I paid the ~$79 price for the Amazon unit and retail from Newegg.
I would prefer to exchange it for a working unit but it's my understanding that Hyperkin makes you pay return postage and then sends and open box "tested" unit back. Is that still correct?