Do I understand correctly that you only won $1.5k from their bookie but they still confiscated $15k? If so, that's thieft 
I tried to find when they changed the TOS with no luck but my Russian friend successfully verified his account no more than a week ago and withdrew all his winnings, so it must be a very recent change. He also told me that Sportsbook is no longer available to him, so it's not really clear how you violate their TOS if they just disabled Sportsbook for any Russian player right after the TOS change.
Personally, I had a similar case when the casino put my country on the list of banned countries and retroactively canceled my winnings, but after complaining to the licensor, they obliged to pay out every penny.
I tried to find when they changed the TOS with no luck but my Russian friend successfully verified his account no more than a week ago and withdrew all his winnings, so it must be a very recent change. He also told me that Sportsbook is no longer available to him, so it's not really clear how you violate their TOS if they just disabled Sportsbook for any Russian player right after the TOS change.
Personally, I had a similar case when the casino put my country on the list of banned countries and retroactively canceled my winnings, but after complaining to the licensor, they obliged to pay out every penny.
yes, you understood everything correctly. My account was red (lost more than won) and the payouts were going well. As soon as my account went green (won $1.5k more than I lost) they requested KYC and took my $18k winnings.
By your definition of “winnings” means your original bankroll plus your 1.5K profit is hostage on the casino?
Do you read their ToS before you play? They knew the fact that Russian players is typically restricted to play in the online casino due to the license requirements. They are using this to hostage your money which they really have a claim in technical perspective due to ToS violation. I’m not aware how the ToS of Vave.com looks like but reading their recent answer to your queries seems like they using your locality as trump card to hold your funds which is really shady.
But they should atleast refund your original balance and confiscate only your profit. This is the downside on playing to casino that you knew that you are violating their ToS simce your country is sanctioned on most services outside your country. They will surely allow you to play and lose but they will do this scammy trick when you are on profit side.