Dyson Air Purifier Return Denial

I bought a Dyson air purifier, and I'm not happy with it. But I can't give it back. The store told me that because I bought it in person, I couldn't get a refund. They said face-to-face purchases can't be returned. I bought the same product with a humidifier from their website and was able to return it without any issues. The law says that if you buy something in installments, you can return it, but they're not following that. I bought it from their store in Kentpark, Ankara. Please don't reply with "our support center will get in touch with you," because I've already talked to them several times. It looks like 23,000 Turkish Lira will be wasted.