There is nothing wrong with saying "I'm sorry, if I did this for you I would be fired."

Those employees are employed under At Will Termination. Their calls are often recorded for "Quality Assurance Purposes". I don't know that they wouldn't be fired after stating exactly that. They very probably won't have any recourse if they are fired. That's a pretty powerful incentive right there and I don't know that I'd blame them for toeing the company line and getting defensive.

It's easy to armchair quarterback when you don't have to work there.