The badge for September can take upto 24 hours to be "awarded"
So just be patient -- if you have met all the targets it will appear sometime today
@KetendenLinenClothes: To quote the Star Seller page, "Wondering if you earned a Star Seller badge for September? It can take up to 24 hours for your dashboard to update—check back soon!"
Has it been 30 days from your first sale?
@PillowDetails 90 days.
Oops! Sorry! 3 months = 90 days!
You can't get star seller until at least 90 days from your first sale.