Mutation after registration

Dear learned lawyers, I have following questions regarding mutation of land deeds. 1) 5 years ago my father passed away. and 1 year ago my Mother passed away. we are 2 brother and 1 sister. when we are going to mutation for our fathers land property, we found that there are many property are laying in our fathers name in govt. records. but we know some of these property are already sold by our father. but no one done the mutation and so these property is laying in our fathers name. Now we have to pay the land tax for the sold property also. So, please suggest us, what to do if anyone not done the mutation.