Amazon India — pickup of an incorrect expensive product not being done

Address:

Thane, Maharashtra, 400607

I purchased a prajapati gems blue sapphire 11.25 ratti 10.42 carat unheated & untreated (Neelam/nilam stone) 100% original certified natural ceylon quality gemstone aaa+ quality from amazon.in

I received it on 20th feb since it was a lesser carat stone when i received it i requested a refund. The seller willingly agreed.

So a pick was created and the courier was expected to come on 23rd to pick up. The person who came didnt pick up.
Following that i made 30+ phonecalls to amazon from 23rd feb to 2nd march trying to organise the pickup.
Each time i was told wait for 24 hours and pickup will happen. But nothing happened. So i would keep calling and no one tells me what is going wrong.
The pickup person is not coming to my place and not even making a phone call. Simply cancelling it.

Its very very poor customer service of amazon where they dont know what is happening in the pickup team and simply making false promises. To top it up they have no contact information to give you to help yourself. They are any way incompetent to help you.
How do i get my problem solved?