Sounds like you have a typically useless dealer.
Brake squeal is usually caused by-
Worn out pads - replace pads and, if required, discs.
Glazed pads and/or discs - remove and "rough up" with some fine wet-or-dry paper.
Badly fitted pads - either the anti-squeal shims have not been fitted, the piston faces have not been cleaned/aligned or copper grease has not been applied to the rear faces of the pads.
To claim this is a common fault and there is nothing they can do is bull****.
Many garages and 'kwik-fit' type operations offer free brake safety tests. Although I'm not suggesting the brakes are unsafe they will tell you whats wrong.
I always get my cars checked over by an MOT garage as soon as I buy them for piece of mind.
rene
August 2009