My nokia 2720 fold, brought from USA, not selecting bsnl network in kerala.

Ur phone must be sim locked....so you hv to unlock it first so that you wil be able to use any network work in ur mobile....There can be many ways to Unlock your phone. As far as i know unlocking by codes is the simple and safe way. I will suggest the website Unlock-Zone.com which is doing good service and they were recommended highly in the cell phone forums.
I used them to unlock my cell phone. contacted them and within 30 mins i had my unlock code and my phone was unlocked.
Hope this helps.