Replying to a review
The audience is the next reader, not the reviewer. That single fact decides the tone.
Structure, and keep it short
Acknowledge the specific thing · say what happened if you know · say what you are doing about it · move the detail off the public thread with a real contact route. Four sentences is usually enough.
Negative reviews
Never dispute the facts in public, even when they are wrong. "That is not what our records show" reads as combative to everybody except the person who wrote it. Acknowledge, resolve privately, and come back to update the thread if it is resolved.
Positive reviews
Reply to the specific detail they praised. A generic thank-you on fifty reviews reads as automation and devalues all of them.
Always
Sign with a name and a role. An unsigned corporate reply persuades nobody.
Never
Offer compensation in public, ask for the review to be removed, or reply to a one-star review within minutes of it landing — it reads as reflex.