Refund

On the 7th of December 2024 I bought iphone 12. When I tried to set whatsapp the verification was sent to Samsung device that is not link with me, I logged a return on the 13th of December 2024 after 3 working day's I was advised my return was rejected because I didn't deactivate my icloud account. I reply to them asking why did they sell a device that is link withsome else verification info. On the 23 of December 2024 I received another email from them stating I need to deactivate find my iPhone. Till today I never received my refund. Today is the 17th day from the date I purchased the iPhone. Please help me my refund