boundary dispute

As per unregistered partition deed in 1964, the land is 1.10 Acres. But as per ROR 1B (As per records viz, Pass book, Adangal, 1B since last 25 years, it is 1.18 Acres). As per 1.18 Acres, it has been partitioned again among family members in 1998. Now the question is when the survey is going on for demarcation of boundaries, the opponent objects that the land is only 1.10. How to proceed. kindly suggest.