Very disappointed in Cavalier crystals for the last few months.

I can honestly say that I’ve opened over 50 Cavalier crystals in the last few months and I’ve never even gotten one 6 star hero/champ. I keep getting an email saying there was a error in the drop rates and they issue new ones and I still wind up just getting 4, 5 or even three star heroes.
I’m losing my faith in this game because for some reason it’s not working like it used to. I use to get six star champs from Cavalier crystals pretty often but now I can’t even get one. And the drop rates are supposed to be better? I have to question that!