First wife’s rights if second wife fraudulently claims benefits?

A Hindu male died intestate leaving two wives. The legally wedded wife is denied widow pension, but the illegally married second wife obtained the death certificate, claimed widow pension, and fraudulently added her and her children’s names to revenue records. No court case is pending. What should the first wife do? Should she obtain a legal heir or succession certificate? Can she file suit to declare the second marriage null and void under Section 11 of HMA? Can the widow pension paid to the second wife be recovered and given to the first wife?