Can't unlink Apple ID We have an iPad 2. It is locked and can't be activated. We can't remember Apple ID and also the e-mail address which we used to create the Apple ID. We can't also find the invoice to prove to the guys at Apple support that the device is ours so they say they could remove the lock remotely.

Is there another way to unlink Apple ID from the device? Or shall I junk it?

iOS version on the device is 9.3.4.
Finally recovered the Apple ID by going to iForgot.Apple.com and then resetting e-mail password to reuse our e-mail which is linked to Apple ID. After that we reset Apple ID password and now we can use the device.