Attempt For Land Encroachment Through Revenue & Registrar Department

My father owns a land holding a joint patta with my mother. It was purchased before 5 years. After 3 years we found 3 new names added in the patta without any prior information to us and enquired with the Tahsildar who approved the same and understand that the new members where the owners of said land before 4 transactions and now illegally added the name again through this corrupted Tahsildar. When we raised notice immediately towards the revenue department and requested enquiry the said new members sold partial land without our concern and registered one sale deed. Our Requirements 1. Remove 3 new names from patta 2. Cancel sale deed 3. Take action on Corrupted Tahsildar - even with money claim since we face a complicated situation on hard earned money of my father’s complete life, pressure and fall in property value 4. Reduce time 5. Chances to approach high court on any ground.