NEW: Florida pizza delivery worker stabs a pregnant customer 14 times because she was upset about a $2 tipBrianna Alvelo, 22, was upset over a $2 tip after delivering a pizza to the Riviera Motel in Kissimmee and returned with an accompliceThe victim was celebrating a birthday with her boyfriend and 5-year-old daughterShe gave Alvelo $50 for a $33 order but only tipped $2 because Alvelo did not have changeAccording to police, the victim shielded her daughter during the attack and was struck in the back by the suspectsAlvelo faces charges of attempted murd-r, home invasion with a firearm, assault, and kidnapping