Poco india - phone dead after latest miui update

I bought A mobile Poco X*pro from Flipkart on *thmay****
After latest Miui software update my phone has been dead, so I called service center they phone will replace by other phone and will give you other accessories of rate difference. When I submit my phone bill to service center they rejacted my phone and start saying that your phone is out of warranty then i said your mobile company made a defected software update that's not my fault. Then they we understand but company only exchanging under warranty phones. They told me to talk to customer support but they are also not replying.