When they fixed your problem, did it end up being brake related?

If it is brake related, I am assuming you have disk brakes:
Brake pads are supposed to have shims (very thin pieces of metal)
installed on them. It could be that they forgot to put them on, are not
installed correctly or they forgot to put a special compound between
them and the brake pad.

On my wife's 95 integra, I once found a metal cover loose which caused
rattling -- although, I don't remember now if it made noise only when
braking or all the time..
It covers a portion of the back of the caliper.

Hope you find it soon.
Remco