I wrote to their support to connect to the wallet and send the money back. But they replied that the entire system is automated and they can't help.
They would, but at the moment, they probably can't risk the whole wallets of the casino to try to recover your funds. Attempting to recover the funds means they are exposing all private keys of their hot wallets. The major reason is just about security.
Is there really no way out in this case? if these wallets are assigned to some exchange, then the exchange could send the money back?
Even exchanges rarely recover wrongly sent money. I have seen a ton of cases where users lost lots of funds with no help.