usage

There has always been a issue with my usage.  No one seems to be able to tell me why two people can use so much, even with one gamer.  Anyway, on June 18th I got a notice that I have used 75% of my data.  Today, June 19th, I got a email that says I am at 90%.  I looked over my usage for past months.  It is growing.  Heck, in Sept it says I used barely any and that's not true in the opposite direction.  So, how is it possible that I used 15% of my data, 1.2T, in one day.