Guest checked into wrong room and gave me a bad review

[Gp2]

I'm less than two weeks hosting. A guest booked for one night. He checked into a wrong and occupied room. I relocated him to the right room which was very clean. Yet he gave me a poor review based on the the occupied room

[Helen3]

Sorry to hear that . How was a guest able to check into the wrong room? Do you not have locks on bedroom doors? @Gp2 

as a homeshare hosts I try wherever possible to be there to help guests check in.