Not shure it has to be done at a bmw garage.
Is this electrical brake system not also on VAG cars like the widespread Volkswagens?
So one might assume other garages can deliver this service.
The parts alone cost around €90.
One and a half hour labour would be €100.
So you drank coffee and used internet for around €140.
Not bad, hope you enjoyed it!
28k seems rather a short brake life, did you inspect the old pads?
The CIC sytem seems to be a little eager for demanding a rearbrake pad service.....