It was very nice that Sonja waited for us 4 hours when we were delayed at the arrival.
They wrote a very nice guide where they explain how everything works, not only with the apartment but also in the neighbourhood, shopping, beaches, parking, restaurants, things to do... a very useful guide.
They also borrowed us a baby chair and baby carrier when they heard we were coming with kids. That was very nice.
Overall, we enjoyed our stay in Ostia and in this apartment :)