property was sold without some paper work

I bought a flat in 2009 from a builder and financed by bank. Now when I sold it to another person nagar nigam passed map is not in document and whole area is also not registered (one room and kitchen are not shown in map). When I asked builder he said it happened to all other flats too. My flat is sold to that third person and he gave full amount in cash. I want to know that the registry of my flat could be cancelled by him without my consent. I did not hide any legal documents to him