Forgot the apple id, password, and related email. How to reset iPod?

My 7yr old niece got an ipod for her birthday last year. She somehow created an icloud account but then completely forgot it, the password and the email address she associated the account with. I’ve been trying to look for the receipt but so far I haven’t been able to find it. I called apple support and they advised that the only only ways to reset the icloud account is by either providing them with the icloud account address or proof of purchase.

Is there any way to remove the existing icloud account when the icloud information isn’t known? I’ve tried restoring the ipod with itunes but the previous account comes back up and asks for the password.