You are missing the message badge.
Did you have ANY messages you did not reply to within 24 hrs? Even messages from other sellers, perhaps about purchases you might have made, count for Star Seller.
You can check the CSV under the Last Period tab on the SS page and it will show you which messages Etsy has counted against you.
Remember ALL new messages require a response within 24 hrs for Star Seller, regardless of who they are from or what they are about, or whether you think a response is warranted or not. If you get a spam message, you need to mark it as such to eliminate it from the count. You can set up quick ressponse snippets in the message area so that you can send a "thank you" or some other message with just a few clicks.
If you make purchases from your seller account, you might consider starting a separate account just for buying, then messages from other sellers about purchases you have made will not mess with your SS score.
