I played in UK using VPN, deposits and withdrawals fine til now. Should have done my research, and now I can't upload UK documents to verify myself.
Is there any action I can take to get this money? Any forums where I could sell the account? Could I move countries and pass it that way?
Selling your account would be another big problem, because the person who bought your account wouldn't pass KYC because when you created your account, you entered your details. The casino would compare the details of the document of the person who bought the account with your details and would easily realize that it's not the same person and might not unlock the account.
You would have problems with the person who sold you the account, who could accuse you of scamming, and if they have your real details, they could report you to the police and you would be arrested. You can contact casino support and apologize so that at least they return your deposit.