For both Apple and Google it's one of those processes where the support doesn't even really seem to understand how it works (they probably don't know what automated emails are being sent, and what the dev side looks like). They would randomly close cases for "no response" immediately after they replied, ask us to upload something despite their being no way to upload it, tell us to ignore the "your account will be closed email" because it actually won't be (wrong again), etc.
DUNS own lookup page doesn't even let you look up by DUNS number (so we could figure out what company some ancient number was associated with). I bet it's because you have to pay for one of their "solutions" to do this.