Hello @feliciastone and welcome to the community! Try going to apps then clearing the game cache if you're using an android device then start playing a level and it should pop up. That's what I did.
Hello @feliciastone, Hearty Welcome to the Candy Friends section of our friendly King Community
I am sorry to hear that you have not yet received the event in your game!! Actually, the game is in the way that UNTIL we pay few of the regular levels continuously, the Special BGT Event will not be triggered!!
Did you try and play few levels in a row (minimum 3)? If you have not done that, try it and see if you can activate the Troll!!