After many painful days of switching ISPs and no proper Internet, it seems I've found a good one at last. [:http://airtel.in/|Airtel] - the mobile phone service provider now seems to have one of the best broadband service in India. Even the service men who came for installation looked more professional in their work. Good thing is that they even provide an extra land-line that does not require you to pay any rentals.
Shall write more about it soon! :)