Update...
Apparently the free installation offer (which was on when I booked the connection) is not applicable anymore.
The TS guys informed me that I may have to pay 500 bucks ... and then my service got disconnected as the balance ran into negative..
I called the Customer care and after talking till the second level supervisor and some convincing... the 500 was credited back to my account and now things are back to normal...
Pretty close call... Though I am little surprised that the sales guys who talk so much while selling the product did not updated the details in my account...
All in all, they did respond to query immediately, and service was restore with only a day lost...