With a VPS, you need to setup your own monitoring for bandwidth usage, our web panel in client area only gives you total usage, updated daily.

Some tools you can use for linux are:

1. http://bandwidthd.sourceforge.net/

2. https://www.gropp.org/?id=projects&sub=bwm-ng

3. http://dag.wiee.rs/home-made/dstat/

I like to use vnstat, which can be installed directly via the package manager in most distributions.

For example in Debian, you can simply install it with sudo apt-get install vnstat and it works out-of-the-box.

After installation, a simple vnstat command will show bandwidth usage history. vnstat --help gives you all the different options - you can browse bandwidth usage by hour, day, week, month, etc.