Here is a member on eBay that I had a fishy experience with:
jpit5728
Jordan Pittman
148 Oakland Dr
Gray GA 31032-5607
United States
I sold this on 11/27:
eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices
On 12/13 he sends me this message:
Yes I am sending you this message regarding the jake locker card I purchased from you. I have not received it. So I would like my card or a refund please. If I do not have my card or a refund within the next couple of days I will take action. Thank you.
To which I replied with this:
Good Afternoon! I am sorry to hear that you have not received the card. Here is the USPS tracking number: 9101128882300015538382 If you go to USPS.com and track it, it shows that is was delivered on December 3rd to Gray, GA 31032. I would suggest contacting your local post office to see if they have any further information for you. I hope it turns up! Happy Holidays. 
I have not heard back from the member since. It seems they were just trying to coax a free refund out of me. I would strongly suggest blocking this member just in case.