Hi. Thought I had better respond to your comments (as translated). Sounded a little strange to me but i think the problem may have been the mattresses on the floor. We are only set up for an individual or couple but were happy to accommodate 2 more people at short notice, (day before). We had to drag out mattresses from storage and although they were aired, i think they may have contributed to the dust smell spoken about. Certainly wont do this for anyone else again! Towels were freshly washed!
I think translation may have been a problem in our communications as we know the limitations with our place and were very honest with the you. It is small & practical for 2 people. Also we found a couple of ants in the bath afterwards, although cleaned the day before, this may have concerned you.
As far as noise, we stated from the outset that there is some noise from us walking upstairs and informed you that a train goes past nearby twice a day. We were away most of the time, & you were at work a fair bit, so I am surprised in the short space of time you stayed that this would have been cause for concern.
Anyway you seemed to be good people. We didn't have any problems other than preparing extra bedding space.