It is best to go to www.airbnb.com/resolutions.
You should be able to involve Airbnb here, but it seems that there are some problems with the resolution center (what I noticed last week). This is what I think will work to contact Airbnb:
Select the right booking or a random one if that is not possible.
Select the reason: address personal issues with my guest.
There will appear a button with: Contact Page
On this page you will be able to call Airbnb if it is urgent or you can scroll to the bottom and send them an email. They will get back to you quickly.
I hope that this will help you guys! @Shehbaz0 @Andrew108 @Ben68 @Chris46 @Valérian0