@Louis1783 According to many reports on this forum, Airbnb customer service has been pretty unhelpful lately with issues hosts have with guests.
Basically once check-out time is past, the guests are trespassing. If they don't answer messages, try phoning or texting them. If that doesn't work, you or your manager will have to show up in person and tell them they are past check-out time, you need to have the place cleaned for the incoming guests and to pack up their stuff and vacate.