Faulty Xiaomi Redmi Note 10 Pro 8GB 256GB Phone

I bought a Xiaomi Redmi Note 10 Pro 8GB/256GB phone through Trendyol on April 11, 2023. I first used it on April 22, 2023, the second day of Ramadan Bayram. From the beginning, the device always had problems with lagging. At first, I thought it was because of the holiday rush, as others had suggested. But even after the holiday, the phone still had problems, like Google search, the camera, and other features taking too long to work. When I called Trendyol's customer service, they told me that I needed to talk to the seller directly because it had been 15 days since I bought the item. The invoice was made out to the seller company instead of Xiaomi Turkey. So, I called the company's official representative to tell them what was going on. They offered to help me do either an exchange or a refund, but I had to talk to their technical support first. The tech support person told me to send the phone back to them via courier and promised that they would figure out what was wrong and fix it. In response, I told them I wasn't happy and that, since it was a brand-new phone, I didn't want it fixed. Instead, I asked for a replacement or a refund. I told them how important customer satisfaction was and that I expected a brand-new phone to work without any problems. I returned the phone by using the return code that technical support gave me and sending it back through Yurtici Kargo. But when I called again, a different person answered and told me that neither the representative nor o*** Bey (the first authorized person I spoke to) could help me because they get a lot of calls about this issue and help the people who call first. Based on how they do things, I would have to wait 21 days. I told them that if they didn't give me an exchange or a refund, I would use my consumer rights and file a complaint. The person said, "You can complain wherever you want." When I asked about this, they said, "You misunderstood me. I only said these things because it's how we do things around here." In the end, I tried to reach o*** Bey on May 17, 2023, through a phone number ending in 85, but someone else answered. When I called back at 13:34, they put my call on hold. I haven't heard from anyone else yet. I want my problems to be fixed by either getting a new phone or getting my money back.