Hackers keep finding more and more creative ways to access player accounts.  Most time the research shows that it is human error on the part of the player getting phished for example or some other form and not an actual hack.  A good example of this is what happened at bitstamp where they stated they were hacked, but they were tricked into sending 5,000 coins to an imposter.  This was certainly no hack, but 2FA would have prevented your unfortunate situation.  Good luck.