Most dealers would say that... Take off the pulley and take it to someone like Bearing man and order a new one. Let them take the measurements to make sure you get the right one. They would probably not be able to work on a bmw part numer or vin etc.
Any engineering shop can pressfit the bearing for you. You can even do it youself. The bearing retaining marks probably wouls have to be grinded off, but once the new bearing is fitted, you can strike in new retaining marks. I have done this with one of my other cars and three years later I am still good.
Sent from a tiekiebox.