Case filed by property owner daughter claiming it, property sold to us

Actually in 2009 my father bought property from a man who purchase the same from his relative. The owner of property was an old man. Now after his death her daughter put claims on that property. The old man sell that property to his relative and that property is registered in registrar office. My bought the registered property in 2009. But due to old man daughter our registry was on hold coz she puts case in district court. After fight for six years we won the case and got our registry. Now we are selling the Same property to other one but again she files case in high Court for same. We are totally crapped between this all. We can't sell the property even we can't rebate the property. Please advice us what to do and how we can overcome from this problem.