Apple India — Illegal cost of repair.

I bought iPhone XR with serial no. DX3YR6J6KXK2 receipt dated 09.07.2019 under the Invoice No. UNIDC[protected]. The display had gone bad abruptly. It was registered with complaint/query GSX Repair Reference Number G[protected] wherein the display of iPhone which was under warranty having display problem was first told that the cost of repair is Rs.0 however, the service centre charged Rs. 16250/-. The service charge and repair should have been covered under warranty however, the service centre charged money wrongfully. The Service center did not provide any explanation regarding the charges and were not able to identify the reason of abrupt display damage. They said its due to pocket pressure.
This explanation is ridiculous as no where it was mentioned by the Apple company before selling the mobile that this mobile is not supposed to be kept in pocket.
Hereby, I pray/request for refund for above mentioned amount with interest at the rate of 12% p.a.