Amazon India - Package not delivered

Ordered a watch from Amazon for my mom. The seller was cloudtail. Paid the entire amount and it was supposed to be delivered by Jan *rth. But it didn't get delivered and at the same time they updated the order status in the site showing delivered. I registered a complaint with their customer support team. They asked me to wait for a few days. Then I called them back and they said, they can't provide the product or the refund; and their investigation team concluded that the item was delivered. They weren't ready to talk to me on further , said there's some confidentiality and they cut the call. I tried contacting the delivery agent but even he wasn't picking any of my phone calls. This was my first real bad experience from Amazon.