Finally A SOLUTION!!!
I wasted a week, I bought lyf mobile alongwith sim card but once the tower came I was able to call but I was not able to use internet, every time it used to say data has been exhausted.
I called customer care and came to know that I have been given jiofi sim card.
I went to the place from where I took the sim and lyf mobile and again I was given a new sim card, but similar problem again happened to me and again I had to call the customer care and ask for help.They took complain and said me to wait for 2 days later which I called and asked them about the status of my complain.I was again informed from customer care that I have been issued a Jio fi sim card which would only work on JIOFI router.I went to shop again and asked what is happening why everytime I was given jiofi router sim and thank god I bumped in to a good educated representative who checked it.
Here is the main thing for LYF user, check your plan from MY JIO APP->Singup/SINGIN->MYPLANS.
there it was mentioned "Jio Welcome offer-JIOFI" active
Guys when you buy sim card, there are 4 options from which they select, like "welcome lyf prepaid offer(0.0 Rs)"; "welcome offer 4g prepaid" and 2 more.
So you have insist him to select LYF prepaid offer.Once they select that then the the sim is ready to use in lyf mobile.
then you can cross check later from myjio app
for LYF user, check your plan from MY JIO APP->Singup/SINGIN->MYPLANS.
there it would mentioned "Jio welcome offer-Lyf (prepaid)"