Outstanding Refund for Returned Goods

Purchased Alva Aircooler on the 22 December 2024, the item was returned to amozon on the 24 December 2025 as it didn't meet specifications. I received confirmation that my refund will be processed in 5 days, however till to date I am still waiting for my refund. When I call Amazon I'm told that they've escalated my query with their third party and i still don't have my refund. Amazon call Centre gave me an incorrect reference number to query with my bank and my bank confirmed that they can't trace that refund