Product not recieved even after payment

Location/place: Kolkta

Name of company/service: Healthkart.com/DTDC courier services

I had ordered a product from healthkart on 15th of august.They have generated a bill and the company pocicy is of delivering the product within 5-6 working days.The product is not yet recieved by me.Even the Courire company is denying that the tracking ID is invalid.It was a necessary health product.Also asked to refund the money but they did not do so