I have a Windows 7 phone "HTC Radar". How do I force it to the offline mode when traveling in my car? It says it is offline but is still using the cellular towers to play the music as I am adding extra data charges day by day. I have already logged 1.09 GB this month and only have 2GB per month allowed on my data plan. I need to know how to force offline so I will not incurr extra data charges whil traveling in my car. We paid for Premium so we could do this. If we go over our data max this month we will cancel the service.