Hi supportpleasehelp,
We'd like to help guide you in the best direction for a solution. We recommend starting with making sure the device is on the latest iOS version. You can follow the steps here: Update your iPhone, iPad, or iPod touch. If you haven't done so already, restart your iPhone. Sometimes a restart can help resolve issues like this.
Here's the article for reference: Locate a device in Find My on iPhone
"Play a sound on your iPhone, iPad, iPod touch, Mac, or Apple Watch
- Tap Devices, then tap the name of the device you want to play a sound on.
- Tap Play Sound.
- If the device is online: A sound starts after a short delay and gradually increases in volume, then plays for about two minutes. The device vibrates (if applicable). A Find My [device] alert appears on the device’s screen.
- A confirmation email is also sent to your Apple ID email address.
- If the device is offline: You see Sound Pending. The sound plays the next time the device connects to a Wi-Fi or cellular network."
Thank you for using Apple Support Communities.