Defective C50 Robot Vacuum, Amazon  Offers No Support for International Buyers

11 months ago, I purchased a C50 model robot vacuum cleaner from Amazon. It has now gone offline and its battery started draining within 5 minutes. When I contacted Amazon, they informed me that since it was shipped from abroad, they couldn't provide warranty support, and they would accept a return. However, they couldn't provide a replacement product due to unavailability in their warehouse. With the amount I paid a year ago, I cannot purchase a similar robot vacuum now. But since there's nothing else to do, I decided to follow the lesson of not buying anything from Amazon again and went to a PTT branch to return the item with the return code, as guided by a customer representative. At the PTT branch, I was told that they don't accept international returns from Amazon and that they don't have a page interface for providing such a service. I contacted customer service again. They told me to get a document from the PTT employee stating that they didn't accept the shipment. I explained that it's not my responsibility to obtain such a document, that the issue is not my problem, and that it's the company's responsibility to resolve it. They assured me they would resolve the issue within 72 hours, but I didn't receive any further communication. I called again, but I had to explain the same problem repeatedly to different customer representatives. Today, I spoke with three different people, but we couldn't find a solution. We prefer Amazon to avoid experiences like these, but it seems that business operations in Turkey have become quite mediocre.