Not enough gold bar reward for Match the Greens Challenge

Hi there. I did finish the "Match the Greens" challenge in Candy Crush Saga. But I did not receive enough gold bar reward. I would get 30 gold bars after reaching 10,000 green candies, but I just got 12 gold bars instead (8 before the challenge and 20 after finishing the challenge). My facebook account has synced with my phone already. Please check for my issue.

P/S: I used my facebook account to log in the forum.