Delay in getting family pension for my nephew. I am his legal guradian

Hi.. my case is related to delay in getting family pension for my nephew( i am legal guardian) due to fault of disbursing branch, followed by CPPC followed by concerned office .In detail now, My elder sister was getting family pension after sad demise of her husband in JUN2004. My elder sister subsequently passed away in Jan 2010 due to cancer. I obtained legal guardianship of my nephew then. Since my sister died in Tata Memorial hospital in mumbai and we are from Guwahati, it took us some time to obtain the Death Certificate. Finally in May 2012 i submitted the PPO book alongwith Death certificate to the pension disbursing branch for further action. Chain of action is disbursing branch fwds to CPPC and CPPC to CPAO. CPAO gives order for cancellation of PPO and issue new PPO for the child. I have been regularly writing since 2012 as follow up to the branch/ CPPC/ CPAO asking for update or action taken. No office have ever responded. I have copies of letters. Finally in 2015 i used bot