Computer v. phone data

[Wainuitech]

My first thought is why are you using so much mobile data, emails and web browsing won't use nearly that,  video is the main data use culprit.  

Do you have your phone/tablet etc set to use the wifi at home when at home, rather than the expensive mobile plan?   Unless you watch a few videos while away from the house I can't see how you would use that much data TBH.

Same thought -- Wife had that happen a few times, her phone didn't auto switch over to our wireless when she got home from work. It was set to switch to a wireless network at both work and home, then one day got a message saying mobile data almost full after about 7 days.