Myntra.com — missing delivery item

This is with reference to the order no.[protected]-7705201 placed on july 13th, 2019 at myntra.com. On july 18th i noticed the status of one of the items tommy hilfiger - men navy blue printed round neck t-shirt was delivered on 14th july but i had not received this product. I immediately called the customer care and they told me that this t-shirt was delivered with another tommy hilfiger tshirt (In the same bag) on july 14th. But i had reeived only 1 tommy hilfiger tshirt in that bag. I have attached a snapshot of the order status here. Also the message i received from myntra after the delivery also mentioned that the bag contained only 1 tshirt on july 14th and that was the other one (Refer attached snapshot). I kept explaining this to the customer care executive but he only reinstated that i have received both the tshirts since they were in the same bag.
He also informed me that he cannot register a complaint for this as the complaint has to be filed within 48 hours of delivery. I politely asked him to at least register a complaint so that they can investigate the matter at hand. Since i had not received the product they would easily be able to trace it in their warehouse but he refused.
This was a prepaid order and i have already paid for it but haven't received the product. Why should i be suffering because of a mistake that was done by myntra. I feel i have been cheated and let down by them. I am a long term customer of the website and would hate to stop shopping from them. But this incident has put the company's credibility in doubt.