1- Slow Bet Grading: Sometimes the bets are pending for hours even after the event has ended.
You are right I have faced this issue too and contacted with them, still they took long time to credit the fund.
2- Support: The support is unable to help in most cases and ask to wait, at least the support should be able to settle the clearly won bets.
Support cant any help regarding cancel or settle any bet either that is on behalf of the payer or not.
3- No sports based contest or promotions: I mean there are so many dice contests always going on but we cant even use bitsler coin for sports and there are no contests specifically for sports.
Also, there is no waggered bonus for sportsbook.