iPhone is magically consuming data when not connected to 3G

its magic, tell you. purchased iphone 4s in netherlands vodafone. allow use 60 days year outside of netherlands in other eu countries.
last week visited paris , phone worked fine , texting too, every time tried use maps or email or other data app wouldnt work. error said "could not activate cellular data network" "pdp authentication failed." (i attached screen shot)
returned today , went vodafone shop , had no idea going on. had me call customer service line gentleman said not working, used 150mb of data while there.
must magic. because wouldnt work when attempted use it, works them bill me.
has experienced similar? apps let monitor other apps data usage? crazy believing in magic?

 

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i've never had this, iphone lets me monitor data usage. me there "usage" tab in settings.

 

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