I have activated a 9 pack at 6AM, and i got the confirmation message that 9 rs 30 mins plan is successfully activated, but i am yet to use it.
I can use it for 30 mins before midnight 12AM. So i just remove the sim from mobile and put it in data card and the s/w gets opened and 3G is shown. I use it for 30 mins and disconnect.
Then again, i do the same process of sending 3G to 121, then it says 3G is already active, if you want to change plan or stop 3G, send 1, send 2 etc. Then you send the corresponding digit to 121 and it is over.
Then start activating another pack again, same story.
But this is for data card.