Hello Jeanjr11.
Thank you for reaching out in Apple Support Communities. Here's detailed information if you can't locate your lost device:
- If you're using the Find My app, you can't see your device's location if more than seven days have
passed since its last location was sent to Apple.
- If you're using iCloud.com/find, you can't see your device's location if it's powered off, the battery has
run out, or more than 24 hours has passed since its last location was sent to Apple.
Here's more information: Use the Find My app to locate a missing device or item - Apple Support
Also to play sound for your missing Beats, your device will need to be within Bluetooth range. Here's additional details:
If they are online, the location of your Beats will show on the map and you can choose Play Sound2 to find them nearby. A confirmation email is also sent to your Apple ID email address. If your Beats are offline, you see Sound Pending until they connect to a network. Once connected, a sound plays and a notification is sent to you.
This information is outlined here: Find My - Keep track of your Beats
Best regards.