2012 Prius Three subtle vibration buzz

my name is Emilio i just gut a prius 3 ,2012. On March 2013 with 14,00 miles on the car.on 09/12/2013 alway had vibration but they suppost to fix that when they balance the tires even put four new mechelins primacy car still has vibration . Master tech. and toyota said car operative as designed. I am doing the paper work to go to arbritation. Car has 31,000 even drove one at dealership new same problem . Can you give any ideal base on what happen to you . Will really help me out.thx

 

Ok thx. You had to paid for this right.