Amazon India - refund not issued

On December **, ****, I placed an order for a Oneplus Bullets Z* wireless ANC neckband using my Icici credit card, paying Rs. **** with Amazon India. I placed an order from my friends account as she had a prime account. Upon using it for a couple of days, I discovered that the product is defective. After I brought up my problem with Amazon customer service, they said they told they will arrange a call with the Oneplus service center to verify the issue. They verified the item's fault and extended an offer of a replacement after speaking with the One Plus service representative. I lost faith, therefore I asked for a refund. They said that after uploading the report, you can contact Amazon customer support to arrange for a return and refund. After speaking with Amazon customer service, a return was scheduled for December **, ****.The delivery person examined the item I provided and picked it up. The transit process was delayed following pickup. When I checked the return status after two weeks, it indicated that the package had been lost in transit. I then requested a refund by speaking with customer service. So on January **, ****, I gave them a call and raised my concern. The customer service agent requested to call on January **, ****, as they need to conduct further investigation. When I called them precisely on January **, ****, they informed me that the investigation was completed and that because they had received the wrong item and hence refund would not be issued. I was quite discouraged and questioned how I could be at blame. I explained them several items and told the delivery person checked the product and then only he picked it up. But they never listened and made me look like I took the product. They said they were unable to help and couldn't provide a refund. In addition to taking three weeks to complete, I lost my money and did not receive the product. I asked them what product they had received and if they had received the wrong one. Initially, they said it was some junk they had received. That doesn't seem to make logic to me. Speaking with many customer service representatives, a few reported receiving different neckband not the original, and a few said they had received junk. I thus requested that they return the faulty item. They refuted. Everyone said there was nothing they could do to assist me and that there would be no refund. They even said you could speak with any senior and you would always get the same response. It was evident to me that they were attempting to hide their error. Furthermore, they treated me really rudely and said that I was to blame for everything. All of this has harmed my mental health. I would attach my evidence to prove my claim.