I was given keys that didn't work properly. It took me several minutes of fiddling with the keys to get the door to lock when I first left the house, so I called the person who had let me in to say that I was afraid I might not be able to open it again. He told me to call him if there was trouble. When I returned, I could not open the door; after trying for some time I called and wrote the host, but no answer. It was late at night so I had no option but to sleep in the doorway. Every few hours I tried the key again and around 8am I managed to open the door, so I guess that the key works in theory. Perhaps it was understandable that they did not answer late at night, but this was about a week ago and to this day they have not replied to any of my messages.