Car vibrate when you brake

<p>My wife's polo vivo vibrates when braking. It was serviced about 2 or 3 weeks ago and it's still under the maintenance plan.</p> <p> </p> <p>When we were driving down to Durban the it was getting worse and scary. Saturday 2nd of july i took it to Barons Durban and the guys there where willing to assist but they told me that the policy doesn't allow them since the brakepads are 4mm and that they've to be 2mm before they can change.</p> <p> </p> <p>I don't think anyone would be happy to drive a car that vibrates when you hit the brakes.</p> <p> </p> <p>Please assist us in this regard as I worry about my wife safety.</p> <p> </p> <p>Regards,</p> <p>Papi</p>