Cannot reset my iPhone even with Activation Lock removal from Apple.

This is a long story so here I get to it:

1) My dad comes to me saying he's forgotten his Apple ID password, and so have I.

2) He no longer has access to the email associated with the Apple ID and doesn't have a phone number or anything else attached to it.

3) I backup all the files on my Dad's iPhone to my PC using the iTunes App.

4) I apply for an activation lock removal form with Apple, give them sufficient proof (literally just the receipt from when he bought it).

5) A night goes by and I receive this:

6) I try to reset my Dad's iPhone to factory new but I am met with the page that is asking for the Apple ID password. I sighed so hard upon seeing that.

Is there anything I'm doing wrong? Or is it a fault on Apple's end? Please let me know.