Has anyone noticed a large increase in the GB usage at the end of their year statement? and never had this problem before ever?

Same here, This is the second time this has happened last month cycle and this month cycle it has happened, I went over because of 2 days went over 180+ gb each! and this is the second time. I talked to a supervisior said he will escalate the issue and see if I can get credit for the overages cause he said your past data never went over until your last two data cycles.