I have had one heck of a time trying to get paid out from the AirBNB Host Guarantee. It is basically a guarantee to be a pain in your neck. My advice: keep calling, over and over, and over and over. Try to find a rep that sounds informed and helpful, they are about 30% of those who answer the calls. The resolution center is a pain too. Take lots of photos and make your rules extremely clear.
With persistence you can usually prevail. The last time I asked for funds from airbnb it took nearly 4 weeks to actually get a resolution!! I got the money and the guest was understanding - luckily that guest did not actually leave me a review so it wasn't negative, otherwise they were great guests who simply broke a piece of furniture.
Persistence is key and don't give up. @Alex Nicholson, do you require a deposit on your listing? That has been my saving grace each time. I require a $200 deposit so that I can at the minimum get that amount and the guest knows they may lose it.
And yes, they can remove some negative reviews I have been told - but again, you have to really work hard to get them to do it.