The withdrawals definitely work, some hacker just withdrew all of my BTC's!!
We are sincerely very sorry to hear that you have been a victim of this kind of fraudulent activity. From the information we have it looks as though your private data was stolen and used to gain access to your account to change your password. You can contact us for more info.
Despite your belief, Mt.Gox has not been hacked in any way and trading on Mt.Gox is still safe/secure. The way in which your account was taken over proves this point (again, you can contact us for more details).
That all being said, regrettably, it is to late for us to do anything with respect to recovering your funds.
Besides general security tips (strong passwords, not clicking links in emails, not opening unfamiliar attachments) to try and avoid this from happening again, our only suggestion is to buy a Yubikey. If you are not familiar a Yubikey operates as a 2-factor, one time password and thus, will make your account impervious to these types of attacks as the attacker would require both your password and the physical key to gain entry. Us asking you to buy a Yubikey may seem like salt in the wound after you've been victimized like this, however it is our sincere suggestion that you get one if you continue on as our customer or even if you decide to join a different exchange.
We also hope that this experience will not turn you away from using bitcoin in the future.