Well, if these cards are legit, then why don't you sell them on localbitcoins/paxful for more profit? There are people who are willing to buy your amazon GC for around $690 right now when the price of BTC is $600.
I doubt your method isn't blackhat. Otherwise why would you take no responsibility after sale?
People buy physical gift cards w/ receipt and all for that amount. Check it out yourself.
These I am offering are E-CODES.
I do not take responsibility as I have no power over what happens to the gift card once it gets redeemed. It might be used along with carded gift cards, on cracked amazon accounts or in complicated fraud procedures of transferring balances and cashing out via a seller's account, just to name a few examples.