Request for refund for missing item in my order

On the 18th of December 2023, I bought four items and only three items were delivered on the 22 December 2023. On the day of the delivery, I wrote an email, and a reply was received on 23 December 2023. The customer care agent by the name of Abulele X informed me that the matter had been escalated to the warehouse department. On the 5th of January 2024, I wrote to Payflex to assist me to get a refund from Superbalist. I received a confirmation from Payflex that an email was sent to Superbalist but there was no reply from Superbalist. I need a refund for the OJ Peak Cap Navy which was not on my package. The order number is ***1