Why do the crates not give characters anymore?

Question for Zooba Zoo Battle Arena

Why do the crates not give characters anymore? In the last update(before end of August) in another account I would get a lot of characters. My dad paid 10.99 euros and I went in the shop and bought an emerald case, did not get any character when there was a 50% chance of getting one. But I am sure you're going to say it's because I'm not lucky. Well no that's not the case, in my other account I would get a character from a gold case even with 5% chance. In my normal account, even with a 25% chance of getting a character, I still could not(gold crate). Why do they put low level characters with very, very high level characters, once I was playing with my level 6 nix and there was a skippy level 11 in my game. This happened more than once.