Vinod bhai, this link is for checking Balance only, not sure how to check data usage, bcoz I use Unlimited plan
But your modem software must be showing the data usage, if you install uninstall it regularly like me, then you can use some third party softwares.
I am using NetWorx-->
NetWorx : bandwidth monitor, connection speed test & traffic usage log
Its a free software and it will show you data usage in varoius ways, like daywise, hourwise etc.
It also shows UP and DOWN Speed in Taskbar.
But it has a disadvantage, it doesn't calculate the speed of hotspot, i.e. if you are using your
laptop as a wifi hotspot for mobile, then this speed will not be shown otherwise its a good software, working fine for me.