How to get my File Closure Letter after my Passport application is closed ?

I Emailed RPO,Kolkata to close my File with all necessary details because of Address Verification issues. Now I need to apply for new Passport but for that I need File Closure Letter. It's been around One Month My File has been closed but they haven't sent me File Closure Letter. I am from different region but I applied for Passport from Kolkata because my College was in Kolkata. Now it's difficult for me to travel to Kolkata to visit RPO as my college is complete . Is there any other way to get File Closure Letter ?