One star is the rating. Your job is the next reader, not a debate with this one. Match none of the heat. Two to four sentences is enough. A long defense under a one-star review makes the review look more serious.
Do not ask them to update the rating, and do not offer a discount for taking it down. Thank them, say the office wants to understand what went wrong, and give the office phone line. Leave the chart out of it.
If the review names a person on your team, do not scold that person in public and do not defend them with clinical detail. Say the team will hear the feedback, then move the rest offline.
Check the reply on a phone before you post it. If the first line could be pasted under every one-star review you have, rewrite that line so it answers this complaint in general terms.
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