Limited Data Plan – End of Billing Cycle hit with Large Unknown Usage Puts we Over Limit

I have a 200MB limited plan – and I received notice from ATT that I was reaching plan limit.  I logged in a checked and saw the billing cycle was coming up in 3 days - and I had enough MB to get me through it without going over.  I then received an email the next day that I went over – I had a 1MB web browsing session at 3AM on Saturday night – when I was fast asleep. 

 

Now I get upgraded to 2GB for the month for $15 - on the last day of my billing cycle.  I did my work to make sure I was not going over and I failed.  I called ATT and they could not tell me what this was for.  If I have an app that is sucking up Internet while I sleep I would like to know this.  ATT needs to provide the tools to help manage these plans – and not just blindly blame others.  I called customer service and got no help.