Some people really have very little respect for people in service jobs.
However, the situation might be that someone has fulfilled that same request she asked you for, either in your store or another store, and she is having a hard time understanding why you can’t get it done. It happens all too often that employees are clueless, give bad service, don’t care about satisfying the customer. It does not mean you are clueless, I just mean it prepares customers to get frustrated, because they have had several interactions over time with bad service, and this is happening more and more in my opinion.
As your manager I would not be very happy you even threw the papers back at her. I would write you up at minimum, maybe fire you. Did she actually toss them at your body or face? Or, just pushed them across the desk towards you. If she threw them at you I would escort her out as your manager. If you are not able to handle a situation, meaning you won’t be able to say yes to a customer and she is not accepting no, get your manager right away, don’t just keep saying no and think in your head, this woman is a rude lunatic. Your attitude comes through that you don’t care about helping her. A staff member saying no when a customer feels sure it should be yes will never be satisfactory to the customer, unless they have an ongoing relationship with you as a regular customer.
My advice is, and you might already do this, I am not assuming, is always have an attitude of wanting to help and wanting to say yes, even if it is impossible. If you just say no with no explanation you can come across as not giving a damn. This particular customer you describe sounds like an unreasonable bitch, so I am not saying she could have been calmed down no matter how nice you were, I am just talking in generalities.
When someone complains, the answer is, “thank you for bringing this to our attention,” not to be defensive. I saw this at exponential levels when I lived in Memphis, they could not handle a complaint to save their life. Even when a customer just was trying to help and not get anything, the people working at the retail establishment, restaurant, doctor’s office responded in a way that was unreasonable and ridiculous. No ability to take criticism and overcome it.
Always try to put yourself in the customer’s place.
I’m curious, did your manager do what the customer wanted? Or, did your manager also tell her no and get rid of her?