I'm sorry to hear that. You haven't started an account on Atlantis with the same credentials as your account here, have you? You also haven't tried logging in from a screen that asks for your PIN, right?The reason I ask is because the only way someone can steal your bitcoins is if they have your username, your password, and your PIN. Your password and PIN should both be strong. Sometimes people think the PIN should be like a 4 digit code, when in reality it is more like a secondary password to help protect your account and as such should include numbers and letters.