Bought a Dyson V15S and It Arrived Faulty—Retailer Says “No Return After Opening

I purchased a Dyson V15S vacuum from the Teknosa Marmara Forum store on 11/14/2025. When I opened the product only for testing purposes, I noticed technical usage problems and defects. Because of this, on 11/15/2025 I contacted Teknosa customer service, opened a support ticket, and requested a return.
However, the Teknosa store refused to accept my return under any circumstances, claiming that because the box had been opened, the product could not be returned. They completely ignored consumer rights and left me in a difficult situation. They tried to avoid responsibility by directing me to a technical service center and saying that “any action will only be taken after a service report.”
They also attempted to shift all responsibility onto Dyson.

In addition, during the sales process, the representative who handed me the product failed to provide any information about Dyson’s user profile setup, warranty activation, support channels, or product usage. This clearly shows how poor both the sales quality and customer guidance were.

If a product is defective on first use, the responsibility does not lie with the customer—it lies with the store selling the product and the brand it represents. It is especially disappointing to see Dyson, a global brand, associated with such a situation.

I expect Dyson to provide an urgent solution consistent with the value of its brand.
I demand that this defective product be refunded immediately under Dyson’s brand assurance and commitment to customer satisfaction.

Otherwise, I will submit formal complaints to the Consumer Arbitration Board and share the issue across all social media platforms.

I request that the inconvenience I’ve experienced be resolved as quickly as possible.