The booking process went smoothly. I contacted Fredrika for the possibility of leaving our luggage on the last day there since our flight back was late in the evening, and she happily agreed - however, later on she had to cancel since she booked the place to someone else and offered the option of leaving our stuff to the building's concierge (leaving a 20-30€ tip), which we agreed.
On the day of our arrival, I was notified via email, by a coworker of Fredrika's, that even that wasn't possible and they simply suggested Termini's luggage deposit (without mentioning that we would probably had to wait 1 hour in queue to leave and 1 hour to pick our stuff and without offering other options!) We lost nearly half our day because of this and were running in Rome with our stuff to find another, more accessible deposit (StowYourBags for anyone in need).
Additionally, we were greeted by 2 coworkers of Fredrika's which were very friendly but weren't informed about the tourist tax, and of course after our flight and tiredness the last thing we would remember was that.
I then received 2 emails the day before departure not to forget to leave the money (noone would come for our departure so we had to leave the money in the house) underlining that these were the rules as if it was our fault in the first case. This, of course, didn't cover us in case the money were not to be found in the house for whatever reason.
If it wasn't for the apartment which was lovely and much much better than the photos here, the rating would be much lower - but the apartment and whole building was indeed amazing - great area, right across Tevere, spacious apartment, sunlit, with all amenities (but the hairdryer), really a catch for the price.
If you are looking for the airbnb-meeting host and interacting experience then this is not quite the best choice, but for a lovely affordable space close to Trastevere and the rest, I would suggest this house - mind the bad communication.