It's Sirius, not your car... known issue with them and BMWs. Car only displays what Sirius thinks you are paying for. Call them on phone (not BTed into car), and be in a position to have the car powered off (meaning dont call them from in the car while driving). They can then send a reprogram signal.
I found this all out when my wife identified that channel 14 (just some pop station) is available on their web and phone app, but not our car... Called and they enabled some additional channels but not all... evidently some just can be streamed the car. You should be able to get Stern though...