It seems Eric’s main issue was with the location of the apartment. This is something he should have known about before booking. Looking at the map, it is clear that your place is not in the center of Riga. Maybe he forgot to look at the map?
When I checked your listing, I didn’t even see his review on the first page, because it’s not in English. I don’t think it’s worth replying. It would only draw attention to that review.
The only suggestion I could make is to put some photos of your neighborhood in the listing. That would help potential guests understand what to expect.