What to do when you need service and can't turn off Find My

Did you try to remove the iPad on iCloud.com?

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If you no longer have the device or if you're unable to turn off Find My in Settings, you can remove it from your account using Find My on iCloud.com.

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copied from: Turn off Find My on your devices and items - Apple Support

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If you don’t want a device to appear in Find My, or if you need to set up service, you can remove it from your list of devices.

1. Go to icloud.com/find, then sign in to your Apple Account (if necessary).
2. Tip: To sign in without entering a two-factor authentication code, select  at the bottom of the window.
3. In the list of devices, select the device you want to remove.
4. If you already selected a device, select All Devices or (X)  to return to the list.
5. Select Remove This Device. One of the following happens:

• • If the device is online, it can’t be removed, but you can prepare it for service. If you select Continue, the device is marked as Ready for Repair or Trade In for the next 30 days.
• If the device is offline, Activation Lock is removed immediately, and the device is removed from Find My after 30 days.

Note: You can also remove your iPhone, iPad, or Mac by signing out of your Apple Account on that device.

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copied from: Remove a device from Find Devices on iCloud.com - Apple Support

The available methods to prepare your iPad/iPhone for service or repair can be found here:

What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

If your device won't turn-on, or is unresponsive, follow the procedure entitled If you no longer have your iPhone or iPad:

• Try contacting the new owner and asking them to erase all content and settings using the above steps.
• If you lose your device, or if someone steals your device, erase it in Find Devices on iCloud.com.
• Remove your device from your list of trusted devices.
• Change your Apple Account password and turn on two-factor authentication. These actions won’t remove personal information stored on your old device, but changing your password will prevent the new owner from deleting your information from iCloud.
• If you’re switching to a non-Apple phone, deregister iMessage.
• If you’re using Apple Pay, remove cards and passes in Wallet on iPhone.
• If you have an AppleCare plan for your device, you can cancel your AppleCare plan or transfer your AppleCare plan to a new owner.