Legal Heir Certificate and Succession Certificate

My wife has expired leaving a four month kid. Now I have asked a lawyer for legal heir certificate and he took me to the civil court and there on a stamp paper her prepared the legal heir document, wherein it is written as Affidavit and Declaration and within the subject it is written that I am the only legal guardian of my beloved wife as my child is a minor. This document was prepared and signed by the first class magistrate. For claiming my wife's PF amount I submitted this document as the legal heir certificate and the PF personnel refused to accept this as the legal heir certificate. He told me that the legal heir certificate has to be issued by the Tahsildaar and not by the District Magistrate. I have prepared this from Kolkata Alipore court and the PF office is at Bhubaneswar Odisha. As my wife died at Kolkata, so I prepared it in Kolkata only. She was working Bhubaneswar location when she was in a job. Please sujest how can I get the legal heir certificate or the succession certificate for claiming the PF amount. Regards S Parthasarathy