Actually... the bets were not legit and clean, according to
this post, and that the one made the ruling --at least the way I understand it-- was their sportsbook provider. Namely, the one conducting the investigation was the sportsbook provider and they are complying to the findings made by the sportsbook provider.
Is it unreasonable to seek a clearer explanation along with supporting evidence? Even after requesting the betting history, they chose to ignore it. What if their refusal to provide this information indicates their lack of credibility, potentially confirming my suspicions of a scam?
I have to say that, yes, it might point to something suspicious, but maybe they're trying to adhere to their user's privacy policy. I think [based from other thread] they're trying a new approach to protect their user's sensitive information as best as they can, although the evidence they have might be helpful for them to validate their decision.
Nonetheless, coming back to your situation, I gave it another spin and it came to my awareness that you're betting on minor league [as per BC's explanation] and it happened about one year ago. As such, even if they provide the betting history here, we might be unable to track the validity of their accusation --prohibited techniques, which I assume will be late betting, value betting, odds manipulation, arbing, and the likes-- due to the less-than-popular nature of the matches of which you placed your bets, that made it most likely hard to find the record to validate or invalidate their counter-accusation.
In the past, I and other members of the forum help invalidated a counter-accusation by a casino of late betting, but that's done on a major league, and within days of the match, of which we still need to find a way to get the record to match it with the accusation. I honestly don't think we can replicate the investigation with minor league, happened about a year ago.
As such, do you perhaps want to consider CG? They probably have more ways than what we have in our arsenal to check past matches and investigate the allegation. Not to mention that due to the nature of the evidence provided on CG --where sensitive info can be set as private, for the participating parties only-- BC probably more than willing to cooperate and provide your betting history.