Hiw can i register flat on collector land mumbai redeveloped property

Dear Sir/Mam, One of my relative have received a redeveloped flat 11 years ago after there old building was redeveloped. Building is located on collector land .when they where given possession eveyone where given same kind of agreement.so they assumed all formalities are done as committee had told them everthing is correct ..niw when they are approaching bank .in leagal sear h there building is coming regustered but flat details are nit showing and bank is saying since it not coming on esearch it is not registered and they can given loan only is flat show in e search .kindly help me ..if i pay stamp duty niw will my flat reflect in e search ..please help as they want to take mortage loan You can repley me on sonuvyas001@gmail.com or on 9619776574..Thank you everyone who are ginna give their valuable time and knowledge to me