I accepted an offer for my unwanted gift card and mailed it to them with their printed shipping label 2 weeks ago... the order status says they haven't received it yet and they are not responding to my emails. So apparently they just get you to mail them your gift cards and then break all contact with you.
I don't understand how they are still in business, with their stock of gift cards stolen from people. Stay far away from this scam of a business!
Edit... After a month I did receive my amazon ecard, after my forth email, which asked for my original gift card back and a complaint to BBB. Their communication is terrible (can communicate one way only thru email...) and I will not be doing business with them in the future