outstanding refund

I have placed an online order on the 27 March 2025, my order arrived on the 31 March and there was an item missing. Contacted the call center same day and I was told the item is out of stock they will do a refund, to-date nothing in my account and I was to told payment takes 7 working days. I called several times after the 7 working days and I was told my enquiry was escalated to finance and to the manager. Kindly assist me to get my payment.