One of my guests made an error on the reservation booking for one guest instead of 4. Airbnb sorted the extra payment to be made and he says that he has done everything asked of him yet I have heard nothing from Airbnb. If they have the extra payment how do I get through to ask them when it is going to be paid to me?
Normally in such case Airbnb does not need to be involved: The guest (or host) can change the upcoming reservation and after confirmation by the other party everything will be sorted out automatically. So it is not clear to me why Airbnb was involved. But if it is indeed managed by Airbnb, it should be visible in the actual reservation and in your Transaction History pages.