Even if you are saying the truth about BC.game. It’s very hard to prove that by using only the statistics of the result since coin flip is pure random games. I’m not a player of BC.game but this is same scenario with slot games with close source code. It’s very hard to prove if the game is rigged and the only thing we are relying is just the reputation of the casino.
Can you provide proof for the change of algo?
I agree that it is very hard to prove that the casino is cheating its users but I do not think that you can push aside the proof of mathematical statistics like that. If anything, statistics, as long as you have very large sample sizes, would be a very good method to prove that the casino is indeed doing something unbecoming, like changing their algorithm in their own favor. But that sample size would have to be extremely large. So technically it would be possible, just extremely expensive to prove OP's theory. And since OP is going on a whim, based completely on his feeling that something is "off", I do not think its worthwhile to test his theory...
I sometimes get the feeling that I am being cheated, as well, when I am on a losing streak. But that is my own subjective view, based on my emotional state at the time.