Need advise on land issue-karnataka

The registered sale deed in your grandfather's name is the proof of title over the property.  If the Tahsildar is not obliging to transfer the revenue records or for mutation of records, you may seek the help of court to direct the Tahsildar do the needful.  Do not implead the objectors as party to the mandatory injunction suit to be filed against the Tahsildar because you will not get the relief so soon as you would desire to get it.

You should say at what stage, your application for " Mutation" is pending and  how the legal heirs of the seller, was came into picture. First you find out the information and get mutation proceedings in your grand father's name.. In case if the MRO has any objection, ask him to give an "order" what ever it may be.  If you receives an against order, you can go for" Revision" before the Revenue Divisional Officer. There you can succeed. You have every right to go court for appropriate relief against the MRO, but it is not right to do so  at the beginning.