@Sasay0
Looking at your listing you are advertising a private space - but with two bedrooms available and a bed in each room.
I see you changed the goalposts before these particular guests arrived, to allow access to only one of the two bedrooms they expected to have. I think it depends on the communication in advance - if you clearly explained to the guests beforehand that they wouldn't have full access to the space, or given them an opportunity to allow you cancel the booking or perhaps renegotiate the fees.
If they understood fully and agreed in advance, then all is well.
So if you personally think you communicated this as well as you could - and the guest confirmed they were prepared to continue with one room, it should have been the end of the matter. However in the review the guest quotes 'What the owner should have done was to tell me that she sold the other room to other guests too since she decided to do it'.
From the guests review, he mentions 'some miscommunications' - critically he must shoulder some responsibilty for this is he said in the review ; 'I thought it would be okay to pay for the extra person when I arrived with only 3 people'
To me it looks like the guest had a surprise when he arrived and you had a surprise with having to deal with a trio instead of duet.
The end result was the guest writing a review where he starred as the poor indignant victim highlighted with capital letters, egregious adjectives, faux multiple question marks and a few other minor quibbles thrown in for good measure.
Anyway, I guess the lesson here is all about prior communications regarding future changes.