Though I find it completely sketchy for them not to allow the withdrawal at least to go to pending while they hot wallet gets replenished . Normally when he tryed to withdraw his balance should've been removed and the withdrawal to be pending while they replenished the hot wallet .
Maybe Megadice are doing it on purpose ? Going on the probability that if a user won't be able to withdraw / his balance remaining intact on the account the said user might continue to play improving the odds of him losing the balance .