Stay calm and polite. First, find out what is actually wrong and what they will have to do to fix it.
A courtesy car of similar standard has been automatically provided until all is fixed I assume?
I have had two brand new cars towed back to the dealership in the first week of ownership in my time (not BMW - touch wood). It happens, sadly.
13 F20 M135i - AW - black dakota - M-adaptive - business nav - electric seats - front PDC
10 E91 320d LCI - space grey - black dakota - steptronic - innovations - 157s - front PDC
99 BMW Baby Racer - red; 05 Renaultsport Clio 182 Cup - French Racing Blue - Konis - Eibachs - Remus - Turinis