Since I joined EE a month ago I have gone from using 2 gig a month to almost 8 gig in 2 weeks. I have no idea how this has happened as I only use data when browsing on breaks at work, or listening to Spotify on the journey to and from work. My phone is showing 2.5gigs just on chrome in 2 weeks.
Android & Apple phones have a data counter which, if you alter the counting period to match your billing cycle, should broadly match your account usage but also provide an app-by-app breakdown of your data usage.
