Prius Front Brakes Clatter and Pull Left....

In 2010 I leased a new Prius II and drove it until the lease matured. It had 34000 miles at the end of the term. The car performed flawlessly, and did not cost me anything beyond rent, petroleum, and insurance. It was my intention to buy the car at lease-end. However, Toyota made me an offer I could not refuse by upgrading to a 2013 Prius III with all the electronics, sun roof, solar panel, navigation, and etc. I enjoy the new car. However; I need help here. At around 6000 miles the front brake pads began to rattle in the caliper housing on the 2013 Prius when I hit small bumps at low speeds 0-10mph. But; when I apply the brake pedal, the rattles disappear. Let up on the brakes, and the rattles return when I hit small bumps again. When I reported this to the technician at the service appointment, he drove the car and reported that he could not re-create the noise I reported. Therefore; "no problem", and I was told I shouldn't worry about it. I insisted that my file include a note that I registered the complaint just in-case it evolved into something serious. I did the next service at 14000 miles, and reported the same brake rattle situation. Their response was the same. Now; I am at 20,000 miles. The rattle continues; and their is a new issue with the brakes. When I am travelling at speed, and it's time to brake, I feel a distinct pull to the left during braking. Went in for service, and the technician could not recreate my concern when he drove it. He says they resurfaced the rotors during the service investigation. Anyway, I told them to document my concern, The problem continues, and it makes me nervous to think about loss of control in an unexpected panic stop. Have any of you had any brake issues with the Prius? I'd appreciate any feedback. Thanks <[email protected]>