why is my phone still showing lost or stolen?

Turn off Mark As Lost on a device

When you find your lost device, turn off Mark As Lost.

1. In the Find My app  on your Mac, click Devices.
2. In the Devices list, select the device you marked as lost, then click the Info button  on the map.
3. Under Mark As Lost, click Pending.
4. Click Turn Off Mark As Lost.
5. Click Turn Off to confirm.

You can also turn off Mark As Lost from your iPhone, iPad, iPod touch or Apple Watch by entering the device’s passcode (the one you use to unlock your device).

Note: You can’t turn off Mark As Lost remotely from another Mac. You can only turn it off directly on the Mac that you marked as lost — by entering the numeric passcode you set up when you marked your Mac as lost.

If you forget your device passcode, you can recover it using Find My iPhone on iCloud.com. See Use Lost Mode in Find My iPhone on iCloud.com in the iCloud User Guide.

Please contact the Carrier.

Unfortunately neither we, just users like you, nor Apple can help you, except offering you this support article too:--> How to unlock your iPhone for use with a different carrier - Apple Support

For any further question/problem, you need to interact with Verizon and/or AT&T.

Regards and best of luck.

Giulio

If it is blacklisted, please contact your carrier and ask them.

If you mean something differrent, please specify your needs better