Post office interest not added for many years

Dear sir,

I have opened PPF post office account at Nandyal-518501, kurnool dist, AP in the year 2004. Sum of interest payable  on the deposits made from 2004 to 2013 were not added to the account. After Post office became CBS in 2014, from this onward interests are calculated and updated. I am satisfied with the sercvice redered in PPF. Is there any way to proceed legally about the Post office PPF errors. 

Thanks.