iPhone 16 Pro Freezing and Major Battery Drain

I purchased an iPhone 16 Pro in December, and since then I have been experiencing several issues with the device. The phone frequently freezes, which has significantly affected my usage. I have already sent the device to service three times, but each time I was told that no issues were found and the phone was returned to me. Unfortunately, the problems still persist and new issues have started to appear. One of the most concerning problems is the battery performance. For example, when I enter a 40-minute class with 60% battery, by the time the class ends, the battery drops to 1%. This makes the phone unreliable and nearly unusable. I kindly request a permanent solution to these issues, such as a replacement device or a full refund, as the repeated service attempts have not resolved the issue.