Please note that my bets were only on the most prestigious world sports events and my account is fully verified (ID, address verification documents). There is not the slightest reason to investigate.
You have to cooperate with Bitsler team, they are telling you to wait until the investigation is done. Bitsler hasn't blocked your account and withdrawal completely. Can you share the screenshot of your bet slip? As you are KYC verified there, maybe the investigation is based on the sports event and the betting odds update time. Had you placed your bets on live events?