iPhone 16 Pro low battery life and rude customer service

Where to file a complaint for a rude customer service by a Senior executive while addressing an issue on low quality battery life of iPhone 16 Pro? Alongside multiple device replacements and still having trouble in keeping the phone running for more than 8 hours. Experiencing extreme battery drain while keeping all the settings switched off such as location, tap to wake, background services, iCloud syncing, personal hotspot, bluetooth, etc. Faster drain while using features such as FaceTime audio & video, Camera and social media for less than 30 mins