would you mind posting the screenshots of of the message they sent you and the conversation you've had with their support?
just curious, have they claried what kind of abuse or exploit they are accusing you of?
In general I urge, if the administration of this bookmaker read my post, I urge you to change your decision and pay me the full amount of winnings. In this case I will consider that the conflict is over.
I checked their forum representative and it looks like they log in to the forum and post from time to time(usually promotions) but I am not sure if they are going to address issues liek this here in the forum. that being said, I'll leave them a PM regarding your issue with ther gamlbing site just in case.
if you want you can also try posting this issue on casino.guru or askgamblers, they usually act a mediator between gamblers and casinos when there is an issue. they might be able to resolve your issue with the casino.