What should I say ? It is at least very singular that Cristiana and her friends did not complain about anything (heating apart) DURING their stay, but only after they left.
You can take for sure that if I had found dirty towels and lined I would have asked for an immediate replacement. I can't find any obvious reason why they didn't did.
Now, let me to address all the issues raised by Cristiana
As to the heating: it's not me that forbidden Cristiana to use heating; it is our laws that prevent people to use heating in this period of the year (and I let Cristiana to know this rule well in advance). However, when Cristiana arrived there were 26 degrees and today morning the temperature in the house is 21.6 degrees. However, I acknowledge that 21 is less than the 23 degrees they pretended to have in the house and I recognize that you can feel cold if you came wearing only a t-shirt as Cristiana's friend did.
As to the noise: they spent a week end in the heart of the historical center of Firenze; do they really expected to find a deep silence ? Consider also that the lungarno which parallels our street is now closed due to some road works; thus all the traffic runs through our street: I do hope Cristiana will be so kind to acknowledge that this doesn't depend on me...
As to the old furniture: it is exactly as described "Isla apartment... is part of an ancient and historical palace with very high floors and some very old pieces of furniture" and as shown in the pictures. If they do not appreciate old, stylish, furniture, they should have reserved a quite different, ikea furnished, apartment
As to the bad odors: which kind ? when ? from what ? I never had this experience and I can only say that no other guest ever complained about this.
To sum up, it seems to me that Cristiana and her groups were simply disappointed because the house was not as they expected (I don't understand on what they based their expectations, but this is a quite different issue) and not so hot as they wanted (they should know however that also in the winter when heating is on, here in Italy, the inside temperature can not overcame 20 degrees). I can only suggest them that next time they want to reserve an accommodation they pay more attention on the item they are choosing rather than expressing their disappointment with spurious complaints.