Amazon India — product never delivered

Address:

Ghaziabad, Uttar Pradesh, 201011

I ordered iphone 6 for my mother as a gift for mother’s day on may 21, 2018 and it says delivered at their website on may 25 but i never received it. I sent them an email on may 26 and told them that i never received ot, they said that sometime courier marked as delivered so just wait for 2 days. I sent them another email on may 29 and they said they are investigating from courier and will get back to me in 2 days. Nobody called me, then again i contacted them and this time they said that i will either get my refund or replacement by june 3. Nothing happened, contacted again and they said wait until june 7. I sent them another email on june 7 for around 500 words this time as i was so frustrated with their customer service and this time they said provide an alternative contact number and investigation is still going on until june 13 now. I clearly told them in my last mail that i can’t wait any longer and want my money back.