It could indicate that you are not logged in to your user if you are not able to contact the landlord, even though you already bought the subscription.
You should always make sure that you are logged in with your e-mail adress and your password (or through facebook), before you start your search for a rental. Otherwise the system will not be able to recognize that is you searching for a rental.
To make sure you are logged in correctly, check the upper right corner (you might need to click on the three lines, if you check BoligPortal through out apps or the phone). If you can see your name or picture you are logged in. If not, you can log in and contact the landlord.
If you are still not able to contact the landlord, please contact BoligPortal's customer service.