DELL INDIA
Different OS Installed On My Laptop

I recently ordered a new Studio Laptop online with Windows 7 OS. My service tag number is 7VB84BS. But recieved a laptop with Windows Vista Home. Even after contacting the customer care, they told me that I will recieve a DVD of Windows 7 which I can configure. I want the company's technician to rectify the problem or otherwise want the refund of payment.