I did talk to customer service and they said there is absolutely nothing they can do until I submit KYC> They said no one has the ability to unlock my account except the security team, and they cannot talk directly with the customer.
They are afraid because the US has a policy of blaming the site operator for any problems a US citizen might have. This was well visible in the case against the pirate bay where the US wanted the owners of the site extradited because US citizens had access to the site which meant the unlawful acts were committed on US soil. That's why you shouldn't blame the casino but yourself. You made 2 mistakes 1 was not withdrawing regularly and holding decent amount of money there, when you should have withdrawn every time you've decided to log out of the site and stop gambling for the day. It's much cheaper to send money again than risk it being stuck there. Then you chose a random phone number without checking - mistake nr 2.
I'd go with the flow and try to get someone to do KYC for you. Maybe it will allow you to get money back, maybe not, it's not going to be worse than that.