If they are shutting down, they will more interested in ensuring people withdraw their capital and possibly winnings and may not really be binded by any law to pay out bonuses because some of those bonus programs would have come to an end. If they decide to still pay those bonuses, that will be out of their goodwill and if they decide otherwise, it will not be held against them as scam.
You’re right and in addition the OP is looking for the VIP bonus that is not yet complete therefore there’s no current reward that is still claimable for him that Primedice owe him.
It’s like any promotion that has a time limit to claim either the specific duration of the bonus terms or the operation of the service that offering the bonus.
PD will not wait for users to finish the wager to complete the bonus before they will close.