You can always mark your ad as ‘reserved’ on BoligPortal. This means that the messaging system will temporarily close and new property seekers will not be able to contact you. You can still contact the property seekers who have written to you. You can mark your property as reserved under “Advertised Rentables”.
Just remember to reactivate your ad on “Advertise” or mark the ad as “Rented out” if the ad is no longer available.
Note that you can not use ‘reserved’ if your property is no longer vacant. Then you need to mark it as ‘rented out’ instead.