They will resist giving it to you, likely by telling you "it's online on their website". or they will send you to a "contact us" page on their website that doesn't display their corporate address. This is when you know you are winning.
They may still not resolve it on the spot, but when someone sees that notes that you requested the necessary information in order to sue, they will likely fix it in short order.
It's worked for me a few times when it was very obvious the company had policy of telling customers to go screw themselves, even when the customer is right.
There is something about actually knowing how to file a lawsuit for real that seems to motivate them.
I guess the other thing to consider is potentially claiming it as income if you do end up charging them.
The fun part is insinuating you’ll also send it to collections if they don’t pay.
Many places have a policy that invoking legal is a one way street, and once you’ve threatened to sue they will give you the contact details for legal and then refuse to speak to you through normal customer service channels for any reason.
You’re now stuck dealing with the people who’s job it is to mitigate risk, and not those who’s job it is to keep customers happy.
The only time that has been my experience was with companies that were in a growth phase of early existence.
Also, I assume you are calling in with legit reason - so my point is exactly that the "risk team" will start taking appropriate action, ya know, to mitigate their risk. Indeed if you are calling to blow smoke up the company's ass in order to get something for free, you will have a bad time.