Data disappeared

I loaded 7 days 8 gigs of data deal yesterday. Today I get a message that I have 1.5g left. When I check my data usage for yesterday 17 Oct you say I have used 5.81g. This is highly impossible. I have not done any activity that can chow so much data in a day This is absolute madness and ****gery. You are *****ing from us yet your data is so expensive. I want a breakdown of where this data was used and what time. Such madness