If you are from Telangana state, if there is a possibility, apply it through mee seva. File this as a grievance with MRO in writing and get acknowledgment. Also file RTI Application to State Public Information Officer, District collector and seek information as follows:
1. Please provide the certified copy of order/notification/circular/directives that states that MRO issuing legal heir certificate for the general public is barred and no more in force and that states that legal heir certificate has to be taken as succession certificate from the competent court.