My prices are based on double occupancy.The guest increase the number of guests after booking.

[Razik0]

My rooms are all for double occupancy.My guests add more occupants after booking.What should I do?

[Marzena4]

Your listing description is misleading, @Razik0:

"Private room in bungalow · Kandy
Hosted by Razik
11 guests // 4 bedrooms // 6 beds // 4 private baths"

How can you do that?

If your rooms are only for two, but there are more rooms, you must create a separate listing for each room you want to offer.

Now you need to ask the guest to either cancel or wait and book more rooms. Or ask Airbnb to step in and help. But the problem is your listing. 

What would you like to offer to your guests, rooms or the whole house?

[Razik0]

We like to offer rooms only.

[Marzena4]

So you must create 4 listings, each for one room. Each room's occupancy must be set at 2 then, pricing it accordingly - I guess you have a fixed price per room.

And then tell potential guests that if they want to book for more people they need to book more than one listing. If the maximum occupancy of each room is set at 2, they will not be able to book such a room for more people.