The line blaster booster generated by the game, as well as the line boosters I have on hand, won't clear the bottom row (i.e., the row with the "countdown" column boosters). I find it impossible to rescue the 19 pets with the inability to use the line blaster. On the YouTube videos I've seen, the line blasters all seem to work for other players. I also tried to rescue pets using column rockets and they won't work either. The rockets seem to be stopped by the "countdown" column booster. Any suggestions?