If the car is pulling to one side, you may have a kinked brake line when the caliper came off causing the opposite caliper do the work and the other side nothing having no fluid pressure to it.
If so charge that to the guy who forgot to put it on properly for a new brake line,only if thats the case.
Not all brakes squeel, pads yes have something to do with it, but also make sure the fitter has installed the brake pads properly as the metal shims in the caliper may be touching your disc causing it to squeal when you brake.
Hope this helps.
ALso even though you are in brisbane i would reconmend Marty at mw performance it you need any work done ,he is on the sunshine coast , maroochydore though, he did all my brake work and its top notch.