I wonder if they're perceiving it as a threat of legal action - assuming you want to know because you're "planning to sue" rather than just checking if there's something fishy with the paperwork. I'm not trying to make excuses for them - this behaviour is shitty in the extreme - but I wonder if they were thinking "surely the only reason you would want to know that is if you wanted to sue me"?
Here's hoping you find someone else who can help ASAP.