Amazon India - Phone returned but refund or replacement not received

I ordered a Redmi * (Gold, **GB) phone on **th September from Amazon which was delivered to me on **st September. But the phone delivered was faulty. So, after multiple calls and emails Amazon customer service agreed to replace the phone and schedule a pick-up of the phone on **th September. Amazon Pick-up agent picked the phone on **th September and gave my mother a Pick up receipt with a wrong Tracking ID (which I came to know later from Amazon customer service).
The phone was already picked up on **th September but on the same evening I received a message that my pick up has been cancelled. I called the customer service and raised the issue at the same time. So, I was assured that it might be a mistake caused by pick-up agent and wait for a day to get it rectified.
Since then I have been calling and emailing Amazon customer service (Investigations and Escalations team) who also informed me that tracking ID mentioned on the return receipt given to me is wrong. Amazon customer service team is not providing me with any satisfied response other than asking me to keep waiting for product confirmation. Every time Amazon customer service associates give me a different timeline to wait (Somebody say wait for * business day, someone say *-* business days and so on). Some of Amzon associates do not even read my mail when I write one and they just give a generic reply and schedule another pick-up for already picked up product (Seriously WTF!).
Amazon's so called 'Customer Service' has caused so much mental agony.

I raised the issue on Facebook too and again I got the same generic reply from Amazon "Social Media Escalation" team that sorry for inconvenience and pick up will be arranged. Amazon does not even care to read the complaints. Here is the link to Facebook complaint: https://www.facebook.com/AmazonIN/posts/***************