Only the top 10 players can get reward from Star Tournament or Legends Arena. You can see your rank to the left of your name.
If you are in top 10 players, please completely close the game and open again to get your reward.
If you didn't open the game for more than 2 days, you cannot claim the tournaments reward.
If you enter the Star Tournament or Legends Arena, you cannot collect your reward if you login or logout of Facebook. You have to play the events with one account.