bc game, please respond to my complaint
As mentioned above, they did already responded to your complaint. You found out to be multi-accounting. Or were you saying that their findings is incorrect? Though I doubt that it's the case [as casinos usually are very sure when it comes to such situation due to their multi-cross-reference that support their ruling], I'll try to bring this to their attention and see if there is anything that could convince them to give another response.
Actually there is no word about multi-accounting, they mentioned "prohibited techniques", whatever that means though. Sometimes when they mention this it means the player used like bots or something like arbitrage betting. In my opinion though, flagging accounts for arbitrage betting is total nonsense and also hard to prove. Well, whatever it is, they should at least say exactly what he has done wrong instead of leaving him and everybody else guessing. No matter what it was, having a 2nd account doesn't seem to be the problem here.