Hello nightingayle,
Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with finding your lost iPhone. If it is going straight to voicemail, the battery may have died. This article goes over the ways you can find your lost iPhone: Locate a device in Find Devices on iCloud.com - Apple Support
"You can use Find Devices on iCloud.com to find the approximate location of your iPhone, iPad, iPod touch, Mac, Apple Watch, AirPods, and Beats product if Find My is set up on the device and the device is online.
To sign in to Find Devices, go to icloud.com/find.
Locate your device
- In Find Devices on iCloud.com, select the device in the All Devices list on the left.
- If the device can be located: It appears on the map so you can see where it is.
- If the device can’t be located: You see Offline below the device’s name. The last known location is displayed for up to 24 hours. Select “Notify me when found” to get an email when it’s online again.
- Note: If you turned on the Find My network, you can use the Find My app on any device that’s signed in with the same Apple ID to see your device’s location, even if it’s offline. The last known location is stored for up to 7 days. See the Apple Support article Use the Find My app to locate a missing device or item."
We hope this helps.
Cheers!