Activation lock for a device you no longer have. How to remove.

How to unlock an iOS device you no longer have

If an ipad you turned in is still locked with your Apple Id because you did not complete this step when you turned it in, you need to remotely erase and then remove it from your Apple ID account.

1. Sign in to icloud.com/#find with your Apple ID (the one you use with iCloud).

If you’re using another iCloud app, click the app’s name at the top of the iCloud.com window, then click Find My iPhone.

2. Click All Devices, then select the device.
3. Click Erase [device], then enter your Apple ID password. Because the device isn’t lost, don’t enter a phone number or message.

If the device is offline, the remote erase begins the next time it’s online. You’ll receive an email when the device is erased.

4. When the device is erased, click Remove from Account.

All your content is erased and someone else can now activate the device.