My Poco C65 Loses 40% Battery in 30 Minutes While Sitting Idle

I've been using my brand-new Poco C65 phone for about a year. Even when I charge it fully, without pressing any button and without using the phone at all, the battery drops from 100% to 60% within just 30 minutes. There's also a sound coming from the charging port. This problem has been ongoing for about 5-6 months.
Because of this fault, I sent the device to an authorized service center twice in May 2026. Each time, I was told the fault was fixed and the problem resolved, but after picking up the phone, the same complaints continued with no change at all. No fee was charged, and the repairs were done under warranty, but ultimately the problem was never resolved.
Since the same problem occurred even after two repair attempts, I no longer believe this will be resolved through repair. For this reason, I am requesting a product replacement for my device.