When you said BMW Toronto. This doesn't surprise... Similar problem happened to me with one of my new bmw's 4 years ago... Except a differential noise.... took them 5 tries, and installation of 1 wrong part (wrong Diff) to get BMW Canada head office involved to meet me at BMW toronto to discuss their major screw ups and poor customer service... When it happened that the manager and Service advisor were both rude pricks, that pushed me over the edge and BMW head office got involved... A human being can only take so much crap/dissapointment/wasted time, after spending $70K on a new BMW.
I feel your pain.