My Kıyafet Sepeti Order Out of Stock After a Week

I ordered a product from Kıyafet Sepeti, and a week later, I was informed that it was out of stock. If you couldn't supply it, why display it on your website? What if I had been in a hurry and ended up disappointed? The money paid is not a small amount; I paid nearly ₺5,000. Furthermore, they offer to provide a coupon afterward, but they say they'll only provide it after receiving the return. If they accept the return, they won't provide the coupon. Why should I risk keeping my money when I'm not satisfied? This isn't how business works.