@Ann72 @J-Renato0 Thanks a lot for your advice!!
Right now, I am still wondering if I should address them already or just wait till they leave a bad review at the end.
As I said before, they sent photos of things that they dislike and asked why there is no this and that in the apartment. I think it was not a full direct complaint straightly to my face yet, or is it?
When they sent those photos, I already said sorry, explained and tried to offer solutions to make them happy. But based on the way they replied, seems like they were not so convinced.. I don't know if I interprete too much here... Should I contact them anyway, ask if they are satisfied and offer the free day like you did @Ann72?
Additionally, I read the reviews of the previous hosts yesterday (I indeed should have done that before hehe - my bad), they even broke things and kitchen appliances in the previous hosts' houses. That does makes me quite anxious. These guests rent my entire apartment so I guess, I have to wait till the end to see if everything is ok or not.