defect pcs

Location/place: navi mumbai

Name of company/service: seventy mm

I have purchased from online(seventy MM) one akash tablet but they have deliver to me defect pcs and now they r not agree to give me my refund Amount

Purchase From:Seventy MM online Side
Purchase Amount :2990
Order no :141899
Deliver By:AFL Courrier
Invoice No : CSD061213000547
My Contact No:8082432872