I have Unlimited account. downloaded lot of music and stored on SD card in the phone. While off-line (no cellular data - in plane) sometimes plays but most of the time doesn't want to initiate playback of my stored music... need to connect to cellular data and magically it start playback. Off-line mode is not off-line indeed! Also amazon does not allow other companies to use their API. So no integration with all streamers except of b***nd. No integration with Volumio and other RPI op.sys. SHAME