Asus - My phone is in Asus Service Center for more than 35 days now and im still not getting any update on

I have submitted for my phone which is under warranty to ASUS Service center for Repair on **th of September ****.
Initially it was told that my phone would get repaired in ** days and ill receive a call from the customer service center.
After ** days i got an email i.e on *th of October that the spare parts for the phone is not available and as my phone is under warranty i would receive a new phone.
But as of today i.e **th of October **** i havent received any update on the issue.
Everytime im calling the customer service they are telling that they have no clue when my phone would get delivered.
As a customer who paid ***** for a phone im concerned that for a company as big as ASUS has no responsibility towards their customer.
I tried escalating the issue to their higher management but it seems that are not at all bothered to provide any update or give a call back to discuss the issue