Activation Lock not recognizing my Apple Account after iPad removal

I have removed the Ipad from the list of devices and still get the activation lock; I have entered my Apple account email and password on the activation lock request on the Ipad but I get the message that "The Apple account c............@gmail.com" cannot be used to unlock this Ipad.

The activation lock message says: "This Ipad is linked to an Apple account. Enter the Apple account and password that were used to set up this Ipad c............@gmail.com.

First I am asked to use the Apple account email and then that it cannot be used to unlock it! Please help!

This is driving me nuts!

[Re-Titled by Moderator]