Can be re-opened the case of succession certificate ?

Hello sir , My name is Amar , from mahabubnagar dist , telangana. My father has died on 25 dec 2010 , and he is a government retired employee. My mother is second wife to my dad , The account general has advised to submit the succession certificate in favor of my mother for grating family pension of my father. I filed a case in the year july 2013 and the judgement by court on september 2015. in district sessions court for certificate and they examined and asked the department where is first wife of my father , they had only customary divorce written in the bond . And the court has published the paper add for 2 months where she is living. After so many months , we only called her to come to the court and she came to the court and told i don't want any money of my earlier husband and was left him for more 32 years . Please pay any amount to second wife and i don't have any objection to pay her any claiming from department . and the court has taken her statement and recorded and duly signed in-front of judge and she left away to her village . The court has issued the succession certificate in favor our family members names and my mother name with paying court fee .The Succession certificate we submitted to the department and the department has sanctioned pension amount and arrears amount of my father. we are receving monthly pension since 4 months . Recently we agot an issue that the first wife has a daughter .and left her while she gone away from my dad . from the day my dad has married to my mother . she lived with us and brought up her from her childhood , my mother has taken care of her at the age of 8 years and she got married to a government employee and now she is a govt. employee right now . And we have given an amount without any document of rs 2,00,000 /- . in the year 2013 . And from the few days my sister of first wife's daughter is black mailing to give an amount of rupees six lakhs to her or else i will call first wife of my dad and tell her to re-open the case in the court that we wantedly threatened to tell positive in the court that she has no objection to claim any amounts of my father. Is it possible can be case re-opened like that or else i should the amount which my sister , d/o first wife . please can you give me a sugesstion . with regards amar , cell : 9063406664