I can't use BSNLLIVE but I can use BSNL NET, Why?

I stay in Kolkata and I have a Nokia C5-03 with 3G. I use Ovi suite on my PC. In connections I use bsnlnet to connect and browse on my pc. But whenever I connect using bsnllive, it connects(460.8 Kbps) but there is no browsing. Why is it so? Is there some sort of activation for BSNL LIVE to use it? I recently used a 3G top up of Rs200=500MB. How would I know if 500MB is over?