Apple India Pvt Ltd - can t replace or refund of my iphone

* months back my sister gift me iPhone ** pro ***GB from the USA.
On ** September **** I plug my phone into charging after ** min when i check my iPhone its overheating and burning my finger. Even for removing the cable from my iPhone, I got a burn on my finger. After cooling down my iPhone approximately * hour I am not able to turn on my iPhone. After that I go to service center they check and diagnostic my iPhone. Even they can not detect serial no of my iPhone this type of overheating is occur. After that on Monday ** September **** I called apple support they told you can submit your iPhone to nearby service center and your phone is going for servicing in Bangalore main service center. If it is repairable then repair your iPhone otherwise replace it. Then i submit to service center. Today I collect my repaired iPhone. But in that serial number and IEMI number get changed and can't show my warranty status.
They repaired my iPhone but can't replace. I want replacement because of this extreme overheat and this overheat is that much affect internal iPhone hardware is not responding so that this is a very big fault or issue from my iPhone.
Only ** min of charging its too overheating even my fingers got burn they repair my defective phone but can't replace it. Very bad experience from Apple.

I am not getting satisfactory answer from Apple support team .
For this ** days I suffering mentally pressure that I can't use any other phones too and even my parents iPhone when I charge I will separately charge in different room because of this over heating issue is running on my mind. I can't control them.

I call almost ** to ** times with apple support team. But can't resolve.
Now I only want refund of my total cost of my iPhone and concession amount because of mentally harassment.