When ur quota is complete, ur internet stops and a pop up comes up (Came in my laptop browser as well as on my android phone) also an exclaimation mark on the wifi logo. The pop up gives u two options. 1. Continue with same speed for another 20GB and pay Rs.X or 2. continue surfing at lower speed.
P.S. Extra money will be charged in next bill
P.S. Extra money will be charged in next bill