Flipkart, laptop replacement

I have purchased a dell laptop just 4days back from Flipkart. For first 3days the laptop was hanging just after i logged in. On 4th day the laptop was having a black screen. I contacted with dell support but they were unable to fix it and proposed that a new motherboard will be delivered to mentioned address by me, and would be fixed by dell technician. But as i had purchased a brand new laptop but it is defective i want a replacement of this laptop and don’t want to replace any parts. Please look into it, its urgent, my work is stuck due to this inconvenience.