Flipkart — Faulty Phone Delivered

I have purchased redmi 10 from Flipkart seller was akshnav online..
Ist they said we will replace your phone if in case of faulty phone delivered..
But when I requested them for replacement but Flipkart customer care said seller is rejecting replacement he will refund you..
they askes me to go to service center they will replace your phone but service center person/customer care said we don't have information related to Flipkart 7 days service center replacement policy...
Plzz help me to get phone replaced.
And i don't want refund from seller i want replacement as they promised me ist...
Thank you