2. They have a restriction, but not stand with their word (If they really care about it, they should block your IP + ask KYC first before make any deposit.
This is one of the shity tactic casino.
I was to say this also. I read their Terms and conditions
2.1. Any kind of sports betting or live betting for players from Russia is strictly prohibited. We reserve the right to confiscate funds and block an account if it is proven that sports betting was made by a Russian citizen.
2.2. Should any of these rules be violated, the Company reserves the right to refuse to pay any winnings or to refund stakes, as well as to cancel any bets. The Company shall not be liable in relation to the moment when they become aware that the customer falls within any of the aforementioned categories. This means that the Company shall be entitled to take the above measures at any time once they have become aware that the customer is an individual who can be designated as above.
Depending on when these clauses were added to their rules like you claimed they were not there at the time you registered, they should have made effort to identify your IP or restricted Russian IP from registering on their website to safe everyone the headache.
My question is did you evade any registration process or using VPN? If you are not guilty of violating registration procedure then they should be able to identify you were registering from Russia.