To be honest, this isn't true. Provably fair mechanisms and their verifiers prove everything if you understand how to use them. With a legitimate provably fair system implemented, it is impossible for the casino to cheat.

What you are likely seeing is just variance. With a tiny 1% house edge, massive swings are far from uncommon. Make enough bets, and you will eventually have a massive losing streak. Remember that there are absolutely no patters whatsoever in randomness -- every single bet is independent of the last, and this is why many betting systems are flawed.

If the casino has a legitimate provably fair mechanism, it is unfair to say it is rigged. I haven't actually had a look at the system used myself, but I assume someone else would have by now. If that maths is right, then it's probably not a scam (in telling outcome of bets, at least -- the site could still run with your deposits).