[Resolved]  Indigo Airlines — last name not added

I girish kumar varshney booked a ticket from paytm, there it didn't asked for compulsory last name so i booked my ticket just with my first name. It was my first time that i booked tickets online and i was not aware of such things.
Indigo refused to update my last name. And there are asking for rs.3000 as my cancellation charge and as it is too high for me, i am unable to bookthat again.