Amazon India — Product undelivered but showing delivered on app. Customer service says cannot do anything about it.

I ordered 1 no of Miraan printed cotton salwar suit on Amazon app. It's showing delivered on 3rd July in the app. It was a prepaid order. My family was out of station due to a medical emergency and when we returned, we confirmed with all neighbours and security but the package was nowhere to be found. It is undelivered. I contacted Amazon customer service today and they said that the return period of the product is over so they cannot escalate the issue. But the item has not been delivered only.