Land

Some people were behind me to sell my land to them at a very cheap rate. I regret and few days ago ,I started giving boundary wall in my land. They then along with cops stopped me doing so. As they are rich police may also with them. Police stopped me without giving any notice in written. And ask me to come and meet in police station. There they just showed me some false xerox of registry paper along with the application of other party claiming that this land was his. Police is doing all these things orally. And has ask me not to work and is saying submit your paper to us with and application. We will see. What should i do? Without any written notice shall i give them xerox of papers? These all things they are doing to harass me,so that i sell it to them at low cost below government rate too. Can i ask the police to give me a written notice so that i have proof they stopped me. And there after can i file RTI to police know about the document on which ground i was stopped? Doing RTI jst to bond police not to change or remove there document later ?