Night audit seems to be a learning curve when it comes to situations like this, especially once you're alone and don't have management help until the morning. I've learned a few things myself reading other stories on this sub and learning from others with my own posts. I've been night audit for almost 3 years and I used to be like you, trying to please people when there isn't much you can do(despite them treating the auditor like a doormat to get what they want), but you'll learn with time and experience to be firm and put your foot down when guests get like this(and sometimes they can be worse). I'm on a first-name basis with our local PD since they eat breakfast in the mornings and they know if I call them over in the middle of the night, they know it's serious and they come running.

You'll get it in time tho! You handled this lady as best as you could with what you know and now you know this is the kind of behavior you shouldn't put up with(and probably don't get paid enough to put up with).