Before coming to Oslo I have been asking Nina some questions which she answered almost always immediately. My friend and I, we came almost two hours later than said and she was considerate enough to text and call me. The apartment is on the highest floor- the fifth floor. You should be aware of that if you are going to have heavy luggage (like we did haha). Although the apartment and the bedroom looks exactly the same like in the pictures, it is smaller than we imagined / in reality.
Nina herself is / was a very nice person and had a lot of experience to give us any specific information we needed. All in all it was a great stay!