Indigo Airlines — power bank I purchased on flight

I was travelling from ranchi, jharkhand to new delhi on 23 october 2017 by indigo flight and i purchased power bank worth rs 1000/- after i reached home and i opened it i saw the piece is defective and its not working at all. Kindly help me regarding this.
Sky water is written on front and its of bronze color. It is very disappointing as my whole money is wasted. Kindly do something