Xiaomi India — too much charge for repair

Address:

Mathura, Uttar Pradesh

Recently i bought mi y1 handset which is approx 2.5 month old. Now its camera is not working and when i visited mi service center in mathura, they told me that it cannot be repair under warranty and they tell the charges of 70% of the purchase price of handset, if repaired without warranty.
Now i want to know that if the mobile is in warranty then why it cannot be repaired under warranty and also why the charges for repairs is that high?