Property issues

3 years ago

We are 3 sons to my father,while property dividing my father make 6 parts of all our land ..iam elder one.. the first choice go to younger one he chooses best 2 parts and second son chooses 2 better parts and lastly i got remaining 2 parts which are totally worst to do agriculture then i told that i dont want these,atleast change one part..so that my younger brother says he would change one part, as per that we wrote letters about what we got infront of villege elders and taken all those signs.. even passbooks are issued and its been 10/11 years..now my younger brother want to return back his part.. and I said sorry i cant i developed this land in this 11 years and i almost payed 3lakhs for motors and borewells and passbooks .. and you never said that you have to return with in sometime.. if you said that time i would argue with Papa and may take another part ... He keep saying i want it anyways, if you start farming i'll ruined all of this .... What should i do now??