Declining family member certificate for Mother

My brother got expired 4 months ago(cause of death suicide ). So when we applied for the family member certificate with including my sister in law, VRO rejected and informed us to apply with out her(brother wife). After that they approved family member certificate for my parents and cancelled again and took original certificate from us, because of the complaint from my sister in law. They Issued family member certificate to my sister in law with adding my mother name(class 1 heir). When we raised this point, MRO informing us to go the court and we(MRO) can not cancel her(my sister in law) certificate and cannot add my mother name in the certificate. What should I do now...?