Amazon India — product delivery and return issues

Address:	Guntur, Andhra Pradesh, 522019
Website:	Amazon.in

I placed an order of redmi 6 pro mobile through amazon.in. It's a prepaid order.
Order no: #[protected]
As shown in the app my pin code is deliverable.
Without even contacting me the shipment was returned to the seller on 4th november. They doesn't even notified me by any sms /mail.
I contacted the customer executive they will replace the product (Redeliver the product) with high priority by 6th november.
Order id: #[protected].
As this order doesn't give any notifications.
I regularly contacted the customer service to track the shippment.
On 6th november they said "product will be delivered by today without any fail".
By the noon of the day the same was repeated the shipment was returned to the seller without even contacting me.
I contacted the customer executive they said the refund is processed.
Wait for 2-4 days to get credit of refunded.
If they notified me that your address is undeliverable so that i can change my address to another location.
It's a worst experience with amazon.
Very disappointed with service.
Probably i doesn't trust amazon anymore.