Trendyol "Available" Coat Vanishes After Wrong Delivery

I purchased a coat from Trendyol, but I received a blouse instead. Upon my request for the coat I ordered, they apologized for the mix-up and offered a refund as a solution. I prefer to receive my product instead of a refund, but they are adamant about providing a refund. The item they sent was incorrect even though it was the one I ordered and paid for. They recommended returning it instead of exchanging it. I prefer receiving my product rather than a refund. How is it possible for the product to be available after payment, only to vanish upon realizing that the incorrect item was delivered?