I think the problem is that @OP is getting impatient. It is clear in the message that service operation on the legal matter will come back on Jan. 3. The site has promised @OP to give what benefits he has on his lost account if he creates a new account but the process needs for the legal department. To hasten the process, the Duckdice representative asked @OP to sign a message from the address where the deposit come from which I think is fair enough but I think @OP hasn't done it yet.
How about you wait a while @OP, they say Jan. 3 then you can follow up after that date.
First, I think this illustrates one of the major problem we have with casinos, and that is their support, when serious issues that needs urgent attention comes up, this is the only time we get to know if our preferred casino is really customer friendly or not.
With the above said, I think you @OP is a careless gambler, with how advanced technology has become, that you lost or your phone was stolen should lead to you loosing access to all of your accounts, even if you have 2FA activated on them, with the kind of money you control, making sure you accounts are safe and accessible to you at all times no matter what, should have been the paramount thing on your mind, I hope you have your issue resolved in one peace, and after this, take necessary steps that will ensure that loosing your phone does not shut you out of your accounts.
No more blaming on @OP, the phone is already lost, and your blaming won't help in the case either.