Roborock Vacuum I Bought from Hepsiburada Was Defective and Had No Warranty Support

The Roborock vacuum cleaner I purchased from Hepsiburada arrived defective. From the first day, it was leaving dust residue. I called the service, and they said, "We will send you a code, and you can return it for free with this code." They asked for around 9,000₺ to repair the defect. When I asked them if it was covered under warranty, they said no and claimed the device had oxidized, even though this issue has been present since I first used it. I agreed to proceed with the return and asked Hepsiburada to initiate the return process. This time, they requested 1,800₺ for the "free" shipping fee. I asked them to send me the contract regarding this obligation, but they said we should find it ourselves on their website, though I can’t even find the link they provided. I will never shop from you again, nor will I allow anyone else to do so. If Hepsiburada does not accept the return of this product, I will proceed with filing a complaint with consumer rights authorities.