If you look at other posts from those who made this accusations, you will find that Roobet has already answered why his bet was vioded, there is a screenshot of the conversation regarding the cause of this voided bet, the sportsbook provider refunded all funds because there was an error from the provider so I think the problem is on the provider not roobet.
This is even relatively certain, Roobet does not provide the sports bets but also buys them (otherwise Roobet would have to employ its own bookies, which is neither cost-effective nor lucrative) and accordingly passes on the bets placed only to the service provider.
If this happens more often that bets are canceled, this is definitely a reason for Roobet to ask more specifically why the cancellations happen. This must also have a provable reason on the part of the service provider, he can not simply cancel bets on his own initiative, where he would have to pay out.