YADNBU.
I also sympathise - we had similar last year, the wife of a cousin we had never met was doing a European Tour and asked to come and stay for a few days.
We said OK but told her we could not have the time off work (as we'd booked a holiday for the week after her visit) so she'd have to amuse herself during the day to a large extent.
She said that was OK as she was "an easy going type". Turned out to be anything but, she didn't get "the working thing" or how our children had to do chores and help out around the house (we have 4 1 SN). She didn't like any local tourist attractions, I took 2 days unpaid off work to show her a few things but she was bored.
The food I cooked was either too much. too little, too hot, too cold, too spicy, needed more seasoning and so on.
She'd ask for a drink then turn down alcohol, fizzy drinks, squash, fruit juice, milk, tea, coffee even the water "tasted funny".
Her bedroom (one ds moved to a camp bed) was too hot, then too cold, the bed wasn't comfortable, she had too many / not enough pillows.
I could get nothing right absolutely nothing.
There was absolutely no pleasing her, she was rude and uncommunicative in the evenings, once she asked if she could help me - I asked her to set the table and she sat down watching tv and ignored me.
The only thing she did do while here was to copy our entire CD collection (well it felt like it) to her Ipod.
Two weeks later we returned from holiday to find a postcard from her thanking DH and DC and telling me I was a terrible host and mother who hadn't looked after her and made her stay miserable with my demands on her holiday time.
Never, never, ever again will I agree to anyone I do not know staying at our house for any length of time.
Op I understand very well what you have been through - it was the longest week of my life.