@Shannon579 It's less than a coincidence. Your listings only have 11 reviews so far. You're still ascending the learning curve here, so when you receive critical feedback, try to take it on board rather than get defensive or devise improbable conspiracy theories. Nobody is trying to sabotage you here - if they were, they'd be talking about bedbugs, not mothballs.
The odor of naphthalene can travel far in warm, humid weather, so if you have mothballs under the house it's not far-fetched that guests have noticed it (including ones who chose not to mention it). Other things can also generate this smell - such as magnolia trees in bloom, and termite infestations - but with two complaints on the record it shouldn't be ignored.
The guest who said the property needed to be updated gave very specific examples of which features were problematic (old linens, furniture stains). Perhaps the money you invested in renovations was spent on other features? It's hard to tell from your listing photos, as many of them are blurry and lopsided, with time stamps dating to 2016.
The fact that your listings are cheaper than nearby homes isn't particularly relevant to the concerns of the most recent guest. Guests expect comfortable linens and unstained furnishings whether they're spending $200 a night or $20.
