Amazon India — complaint against delivery & false commitment

I ordered a laptop (Order no[protected] on 10.10.2018 and during checkout section, there was a option that delivery within 12.10.2018 is free as my account is amazon prime and there is a cashback option for no rush delivery. I choose the delivery on 12.10.2018 and the item was shipped on 12.10.2018. On the same day i got information that the item was out for delivery and delivery will be done within 9 pm. Also contact number of delivery agent & otp provided via sms. But the delivery agent did not receive my call as i dialled for 15-20 times within 5 pm on 12.10.2018. I contacted customer care at 9:30 pm and i was informed that the delivery will be completed by 10:30 pm and if not, then the prime membership will be increased by one month. On tracking page at 11 pm i noticed that they mentioned "item rejected by you and returning to the seller". I again contacted customer care and they informed that item was damaged during transit and so returning to the seller and replacement will be provided but no time frame provided. On 14.10.2018 at 4 pm i got sms that refund initiated for the product. I again contacted customer care and they informed that as the item is out of stock so refund initiated while the item with same seller & same information is displayed at their site. Every time i got different answer for the same order when i contacted with them via phone or chat.