How to cancel illegal Registration

My father purchased the land in 1972 and we are in possession ( Khabja) ever since It came to ROR dispute in 2003 and case went across MRO,RDO,and Joint Collector. The final judgement came in 2010 November in favor of my father We received judgement along with ROR, Pahani for 1ACRES 13 GUNTAS for the 308, 309, 310 in my village of Janagaon Mandal Warangal Dist Telangana state. In mean time during October 2010., the opponent who defeated in this case sold out to Real Estate prior to the judgement without any legal rights on the land. We suffered a lot since agriculture land converted to plots. We invited the real estate people to come for the discussion, finally, we approached police station for the justice. The CIrcle Inspector of police gave a warning to real estate people and seller, he asked us to cultivate, since the land registered and sold out without any legality ownership while the case is in progress. We have taken back our beloved land for cultivation. After 6 months now , CI changed and called on my father yesterday ( 14th June, 2016) to police station to handover the land. CIrcle Inspector of police asked us to file a case to get the legal rights although we shown Pahani, ROR and 1972 registration. He gave full authorization to real estate guys based on the illegal registration. Kindly suggest the justice and way forward action. How to nullify the existing illagal registration. What is the process. Thiru Reddy Sent from my iPad