Xiaomi India - Defect detected within warranty period still asking for money

I bought a Redmi Note*
from Flipkart. From the very beginning I found
that the product is defective, started facing issues and informed to
customer care executive for a replacement.

Instead of that they arranged a tech visit and told nothing wrong with the
product. But issue was still there.

Now the phone is automatically restarted. Though it is in warranty period
still the service centre is asking money saying some internal socket has
broken.