What is your objection to sending them a one page form with your signature, the date and your tax id number, three pieces of info that Chase already knows?

It's very simple. If they can't verify your identity through automated means, they need a piece of paper saying that you are affirming that this is your correct SSN and that it's on you if you lied. You could have completed one and sent it in the time it took me to read this thread and respond.