Sadly if you actually USE your connection almost all the time for streaming you will eat through the allotted bandwidth caps very quickly.
I use netflix a lot sometimes and if my mother in law is watching stuff on her computer along with my wife and I doing things it gets up there real quick. It's almost as if they expect only one person to be using the internet throughout the month and with a multi user household you may have usage all throughout the day by different people.
The plans with higher speeds come with higher caps in bandwidth but even then it can be difficult to understand what you are using on a monthly and daily basis since their meter doesn't really break it down much beyond what you have and have left not to mention that there are a lot of questions as to their accuracy. »Cox Having Trouble Metering Usage Accurately
I have a dlink dir-825 running DD-WRT v24-sp2 and the WAN status shows a lot more and makes it easier to keep track to me.
Some info based on the last five months:
September 2013 (Incoming: 212071 MB / Outgoing: 7493 MB)
August 2013 (Incoming: 132087 MB / Outgoing: 5505 MB)
July 2013 (Incoming: 165877 MB / Outgoing: 6568 MB)
June 2013 (Incoming: 184285 MB / Outgoing: 8515 MB)
May 2013 (Incoming: 138569 MB / Outgoing: 6756 MB)
And a typical day:
August 27th, 2013 (Incoming: 10170 MB / Outgoing: 289 MB)
High use day:
September 15th, 2013 (Incoming: 47546 MB / Outgoing: 828 MB)
I can't exactly say "ignore" the e-mail but I can compare my logs to their meter and call BS if I need to and I have never used the provided e-mail addresses anyway so who knows what black hole their messages end up going to anyway.