I was downgraded on my Seller Star rating last because I supposedly did not respond to an inquiry within 24 hours.
The problem here is the automatic threading system, which downgrades you if you don't send some kind of response to an incoming mail, regardless of whether it makes sense.
For example, my customer had simply posted a link to my listing and then hit enter. Then he noticed that he had forgotten to write a text to the link and wrote a second thread with link and text. On the second thread I had then immediately replied.
The problem: I did not reply to the first thread because that would not make sense and I was downgraded by Etsy.
This is clearly a problem in the automatic system that cost me the Seller Star!
Dear developers, you should fix this as soon as possible.
Translated with www.DeepL.com/Translator (free version)
You must reply to all messages or mark as spam.
I'm so sorry you found this out the hard way. But yes, you must respond to EVERY message.
Many buyers send duplicate messages or multiple message threads about the same thing. In that case, send a simple little response, something like "Please see my reply to your other message". That way you have responded to all of the customer's messages AND if they happen to miss one response, they'll see that and go look at the other message. This is something I've been doing since long before star seller and it seems to work well.
This is changing next month (/or when they've worked out the bugs)