You can easily contact amazon support and say your account was hacked and get it reset to your original email. They check IPs. This is highly unsafe.
Everyone please trade with caution.
Anyone can do that and if you have doubts about a seller I suggest not dealing with him or even commenting on their post, to be honest your post was just to raise your post count on the forum, it's not constructive at all.
For a gift card that is not used, where do they check these so called IPs and all that information, I have bought quite a few gift cards and would like to avoid this in the future.