I used this exchange in past to buy something but bcoz of late deposit i cancelled my plan and withdraw all money .
in any centralized exchange you can not be sure whether the hacker or scammer is any insider or outsider . in past many exchanges blamed hackers for lost fund but in reality this was not the case . however i am not blaming bluetrade but as you said even after 2FA someone stole it , so seriously big issue in their system . if bluetrade team already replied you then i dont think there is other options left to recover this fund . but next time use trusted and popular exchanges for trade .