Was not able to open the door with the key. Later, found out that a bit of skill was necessary, which was never explained earlier. The host demanded for a taxi fare when he asked to come over to show how to use the door key. After he opened the door, we had to pay him Euro20 upon his request. While waiting for him outside, we saw him approaching to the residence on foot. Apparently, he seemed not taking a taxi then. Not so sure if such happenings are occurring repeatedly or not.