Mango Sent Wrong Item for My Tracksuit Set and Won’t Replace It

I ordered a tracksuit set from Mango during a sale, but they only sent the top. Instead of the matching bottoms, I received children's pajamas! I immediately requested an exchange, but was told that the product is out of stock and that they can only offer me a refund. This is unacceptable—where is my original item? It’s clear that the product I ordered must have gone to someone else, leaving me without what I paid for. Mango’s handling of this situation is causing serious customer dissatisfaction. I don’t want a refund, I want the tracksuit I ordered! Mango, resolve this issue and send me the correct product.