The first thing to establish is who the response is for, because getting this wrong drives every subsequent mistake. It is not the reviewer, who has already decided and will rarely change their public rating. It is the next twenty or fifty people who read the profile while choosing between you and somebody else. What they are trying to learn is how you behave when something goes wrong, and your reply is the only direct evidence available to them.
That reframing changes what a good response looks like. Winning the argument is irrelevant because the reviewer is not the audience. Appearing measured, specific, and willing to fix things is the entire objective, and a reply that achieves it frequently does more good than the review did harm. Readers routinely report trusting a business more after seeing a fair response to a complaint, because it demonstrates something a five star profile cannot.
Wait before writing. The reply you draft while annoyed reads as annoyed to everybody who sees it afterward, and it is permanent while the annoyance is not. Draft it, leave it for a few hours, and read it again before posting. This single habit prevents the majority of responses businesses come to regret, and there is no version of this situation where a few hours of delay causes harm.
Keep it short and factual. Acknowledge that they had a poor experience, state the relevant facts plainly without adjectives, and invite them to contact you directly. Three or four sentences. Long replies read as defensive regardless of how reasonable the content is, and every additional detail gives a determined reviewer something further to dispute in a follow up that will also be public.
Correct the record without calling them a liar. There is a meaningful difference between our records show the work was completed on the agreed date and that is not true. The first states a fact and lets the reader draw the conclusion. The second is a confrontation, and readers side with the customer in a confrontation almost regardless of the merits, because they identify with the customer rather than the business.
Do not disclose details of their situation in the reply. This matters more than most owners realise. Naming what somebody bought, what they were treated for, what they paid, or anything else about their circumstances can breach privacy rules depending on your industry, and in health related fields it is a regulatory matter rather than an etiquette one. It also reads badly regardless of legality, because it demonstrates that you will discuss customers publicly.
Report it if it genuinely violates platform policy, and set your expectations accordingly. Reviews are removable when they contain a personal attack, when they are from somebody who was never a customer, when they concern a different business, or when there is evidence of coordinated activity. Platforms do act on those, and the process takes time and frequently fails on a first attempt. What is not removable is a genuine customer describing an experience you consider unfair, which is the category most complaints fall into.
Where a review is from somebody who was never your customer, say so plainly and factually in the reply as well as reporting it. Readers can generally tell, and stating that you have no record of the transaction and would like to understand what happened is both accurate and non aggressive.
Then do the arithmetic that actually matters. A single critical review is devastating when there are four in total and barely visible when there are forty. Volume is the only real defence, and it is entirely within your control. A business that asks consistently accumulates the buffer that makes any individual complaint contextual rather than defining, and the effort of building that buffer returns more than any amount of effort spent on one review.
There is a related point worth knowing. A profile with no negative reviews at all converts worse than one with a few, because a flawless record reads as filtered or purchased. Research on this consistently finds purchase likelihood peaking somewhat below a perfect score. The unfair review you are looking at is doing something for your credibility even while it irritates you.
Finally, check whether there is anything real inside it. Complaints that feel unfair frequently contain an accurate observation wrapped in an unreasonable conclusion, and the observation is usually about communication rather than the work itself. Something was not explained, a timeline was assumed rather than confirmed, or an expectation was never stated. Fixing that gap prevents the next several complaints, which is worth considerably more than resolving this one.