cheasts&key fragment
guys i had 3 s+ and 4 s ranks and a lot of A this week but i didnt got a chest or a key fragment on any of'em why ? (and i got 3 avmolable chests) and the last s+ was 30 min ago with 
2 Comments
in your profile, what does the section 'chests available' say? front page, upper right
You can only get a max of 12 key fragments every 30 days, and the drop rate decreases each one you get so you might not see some for a while.
Also, you can only earn one chest per champion each season, so if you received one on Shyvana already you can't get another til next season. You can check in your Profile in the champions page what you earned them on, they'll have a gold border.
For more specifics on how Hextech Loot works, check out this page; http://boards.eune.leagueoflegends.com/en/c/champions-gameplay-en/KZnWzcGK-hextech-crafting-and-mastery-frequently-asked-questions
If you still can't figure out why you didn't earn loot, I'd recommend posting on Help & Support instead.