i do not get chest

you can only earn 1 chest per champion, which can be checked in your champion pool by scrolling over them and seeing the bronze colored chest, which means you earned one for that champ, or a greyed out chest which means that champion can earn one, but also, you gotta have at least 1 of the 4 chests available to be earned

Players that are punished by the Instant Feedback system, and work off the punishment, are restricted from earning Hextech chests or keys for a period while the system ensures that they have reformed their behavior. There is no fixed interval here - if you continue to play with sportsmanlike behavior, you'll eventually get back into good standing.

Obliusly you can't earn chest with the same champ twice