The process should be simple:
1. You have a 'no guest' rule.
2. They brought in 'extra' people, so 'no bueno'
3. You want the guests out now (the real reason best to keep to yourself)
4. The most Airbnb can do and will do is cancel the reservation
5. If they do not leave then is trespassing. Police matter.
To me, in an effort not to make a federal case out of it, if they are leaving within a day or two, then do the less-disruptive of your life and your neighbors, and the minute they do leave change the codes (of course) and think of the methodology to prevent this situation happening again. Forget Airbnb, they are a booking agency, not local enforcers of the law.