Brake dust on 2009 Chrysler Town & Country

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
Since new I have had 3 times the brake dust on the rear wheels compared to the front.The dealer ,in response to a high speed braking vibration, has re surfaced the rear rotors twice,new pads once and replaced the front rotors. They will not address the brake dust though. What could be causing it? It looks terrible in 200miles.
(1) Answer
Regular brake pads can be quite dirty as they wear, next time have them install ceramic pads and your wheels will stay cleaner longer