I logged into my SkyDrive account using the SkyDrive app on my Windows Phone 9 (Nokia 920) on Sept 29, 2013 yesterday round 12 noon. I have not figured out how to logout. Also,  this situation has made me concerned that I will use up the data usage allowance on my AT& T Mobility account, so I have tried to keep the smartphone shutoff most of the time since then. Can you advise me?