BMW Assist help

[captx5]

Hi, I've just bought an American specd 2004 X5 4.4i sport with Bluetooth and Assist. The system is not yet registered with a service provider so I can't make calls. I pushed the Assist button by mistake (not smart, I'm in W.Africa) and now can't play any music (muted sound). The assist appears to be trying to make a connection (button flashes) and the display shows "escalating call" message.

I can't figure out how to shut it down and have read all the manuals. No reference to stopping Assist calls, only how to initiate.

Help please, driving with no music is

Thanks in advance!!!