A reply was sent for the same case on a different post, see below :
We are sorry to hear that you encountered some issues on your first withdrawal request.
While we always do our best to process withdrawals as fast as possible - within 3-5 working days at most - unfortunately in some rare situations (usually for new players or first withdrawals) our financial department needs to conduct some additional verification for security reasons.
Please understand that these verification procedures are there for security reasons and are meant to protect both, the operator and the user.
In your particular case, there is an ongoing investigation by our financial department and you should have been contacted by our support team to provide some additional justification by now. As soon as the missing documents are sent, your pending withdrawal will be processed right away.
Hoping that your case will be settled quickly, we'd like to congratulate you again for your winnings!
Do not hesitate to get back in touch with our friendly support team if you need any further information :)
The Lucky31 Team