Xiaomi India — mi a1 warranty issue

I have ordered mi a1 via flipkart on 7th of december
And received it on 8th of december

The phone was working perfectly
But recently i got an update
After installing the update my phone got bricked
And there is only bootloop

So i took it to service centre

But there they had refused for the warranty
Stating that the phone has been repaired in open market
But i have not done somthing like that
As the phone was under warranty so i took it to authorized service centre

They said that there is a kind of seal near the battery which is broken
How can i get solution for my device

When receiving i can check for external diffects
How can i recognise the internals