@Dee, it's a scam, since the booking was never confirmed. What you've mentioned is entirely against AirBnB procedure, policy, and rules.
Scammers tend to focus on new hosts, and in this regard there've been a number of postings here on the forum.
Unfortunately, I doubt that AirBnB will be prepared to assist you here (e.g. in helping to get rid of the guest), because the booking was not confirmed. It was - apparently - just a request to book, and she didn't pay via the AirBnB platform. Nevertheless, given that you're a new host, you might try contacting AirBnB to ask how you should proceed.
In any case, you should flag this guest's profile to alert AirBnB to what she's doing.
Meanwhile, you and your partner might consider removing her and her belongings from the premises.
What she has attempted to do is illegal.
I hope other more experienced hosts here will be able to advise.
In addition, it's essential that you take the time to become familiar with how AirBnB operates. Efficient - and happy - hosting is much more complex than simply advertising accommodation and waiting for the guests & the money to roll in.
Here's a link that might be useful. Be sure to click on the FAQ box at the bottom as well.
https://www.airbnb.com/help/responsible-hosting