I am sorry that you had an issue with the kitchen. I had professional cleaning Service for my flat before and you were looking at the kitchen as well while handing over the flat. I am 100% sure, that there were no fruit flies at the time of the handover. Of course I had fruits there, which can always be used by my guests. By staying more than 4 days, it can occur, that fruits become a bit old, but why not just throw it away then?
Regarding the plates...I am using a dishwasher and perhaps there was one or two plates which do not come out perfectly. I will Focus on that more in the future.
By the way...the "water kettle" is my Espresso machine. You cannot cook water with it;)
Anyway, you are always welcome and please adress it directly next time, so I can help immediatelly.