Just sold my Titanfall code on Ebay. The buyer says that the code was already used. Which it was sealed until I opened it to send the code to them. Microsoft checked and can see the code was redeem after they received it but wont tell me what gamertag. Anyone know how to get more info, since Im sure they are going to try to get their money back?
You should have created a shipping label (with tracking/delivery confirmation) BEFORE sending the code, scanned or taken a picture of the code, put the code in the mail, and then sent a message with the picture attached.
That way they would have looked stupid opening a dispute BEFORE having received their product AND if they wanted to scam you they would have had to take the time to mail something back AND if they actually did scam you you could have at least filed a report with the postal inspector for mail fraud (i.e. a felony).
Now you're only real solution is to outwit the buyer.
You can tell him that you're sorry to hear the code doesn't work, that you'll contact microsoft to see if they have found any problems with the code and report back. At the point your only bet is to bluff him---you know it was redeemed but you can't prove it was him (of course he doesn't know that... or maybe he does)