Sometimes .5 to 1 gig of data is used at times when phone is not being used, eg. 3AM in the morning when I'm sleeping, 9AM when I'm at work and haven't used the phone all day etc., this happened until it ran up to 10 gig of data and I was charged overages. I had to reduce plan and purchase the app to cut off data to the phone when it reached the limit of 5 gig which only took 1 week.