BMW Assist will not cancel
 

A passenger in my X5 pushed the assist button, which used to be "active", the phone dialed but now I cannot cancel it. No one seemed to pick up the call but the call was dialed. I cancelled assist about a month ago. Now I cannot use my stereo!
Can anyone tell me how I can cancel or reset this?

unplug the harness to the assist button and see if it works............ worth a try.