We could't tell Mara the exactely time of our arrival, but the communication was uncomplicated and she was available all the time and very friendly. She was waiting in front of the building and showed us the free parking nearby. The apartement was very clean, good equipped with everything we needed and it was very hip and modern. It is located close to the railway - so on the one hand it was a little bit noisy because of the trains (but we didn't really mind it and we have been sleeping very well never the less) , on the other hand the apartement is located very good and you can reach the Metro in about 5 minutes by feet and 2 stations to the Colloseum!
Mara was a great host, she was making sure that everything was okay and gave us good tips about going out for diner, supermarkets and sightseeing.
All in all we had a great time in Roma! Thanks for all :-)