People are now scamming business's for exchanging bad reviews for "free" service...It happened to me recently after a client challenged me for a "unsatisfied" service...Complete lie to the credit card company as they tried 3 times to challenge the charge...I won, however right after I won I ended up giving the money back as she placed a negative 1 star review on Yelp...As owner/operator it's hard to overcome...On the positive side she placed a 5 star review to ease the "free" service...You never know who you'll run into...
If anyone threatens you with a bad review to get a discount, suggest they talk to their attorney first. Demanding price reductions or free services using the threat of a bad review is
extortion. The courts have begun to look very unfavorably on people who do this, in one case making the woman take down all of her negative reviews, post apologies on all of the review sites, and pay the business owner damages.
(This is not the same as a simple negative review! Companies that sue over negative reviews may win, but lose in the court of public opinion. Yelpers are terrified of having to be responsible for their jerky commentaries, and will band together to support the jerk. )
I wouldn't recommend going to court, but I would respond to that negative review with an "outing" of the reviewer and their extortion attempt. It at least would let readers know that there are two sides, and may keep other Yelpers from trying the same thing with you. Then I'd forget about it and go back to burying it with good reviews.