For anyone still playing the Legends mobile game, they have announced its closure at the end of September, and have opened up all the bonuses to players.
It only started in April 2013 year, so only lasted 2 years... but it seems that people moved onto their other "Gen1" game Battle Tactics, so maybe there just isn't enough of a market to support more than one profit-making ongoing Transformers mobile game. Or it just became too difficult to get much fun from it without paying a lot of money for the more powerful cards/characters. (I never played it so don't know, but that seemed to be some of the comments.)