did they stop giving away key fragments?

I do not know. I got 3 keys and 2 fragments last month over 50 games. It's a lot of games... It seems rarer for the first key this month than last month as well. Like it doesn't TOTALLY reset.... when I couldn't physically play enough to get enough keys for the chests in the first place.

They still give key fragments away. I might be mistaken, but if you were banned or punished for something you lose your rights for the crafting system. So if you gotten banned you won't gain any chests/keys I think.

The drop chance decreases the more you get and the drop rate resets 30 days after you get the first one.. supposedly. I got my first fragment 1.5 months ago and the drop rate has not reset for me.