So what's happening when I can't sign my address? I've transferred from my Bittrex account. How can I prove it? I already created a report though.
You will be refunded after the investors with signed messages, I am in the same situation as you, and I also do not know what could be done to prove that (I did a screen from my bittrex withdrawal but Lauda does not seem to take it in account) But you are on the investor's list to be refunded. It's already a good start.
Correct. People that have signed a message are going to be the first ones to receive a refund. Then we move onto people that have provided other forms of proof, and so on. Anyone who has used some kind of web wallet, exchange or similar will be handled on a case-by-case basis. Screenshots on their own are insufficient proof. It is trivial to fake them.
There will also be a time-limit for claiming. We are obviously not going to wait weeks and months for someone to step up and claim their money.