You can find a secret stash of money under the leg of one of the tables in the second floor, press down where you see a crack to inspect it, it's there to actually progress, since the normal gambling process is meant to make it impossible to progress without it.
Pay attention to the number the guy on the phone repeats a few times, you need that exact amount of money, no more no less.
May also need the dossiers, they contain information that explains some things.
Sorry I took a while to reply, I forgot I had an itch.io account or that I even made this game :|
Oh, and Krikiav's dialogue can be completely passed over, it's not necessary to talk to him at the start in order to progress, unless you want him to tell you how much money you got. All you really need is the right amount of money.