If a globalstarbeauty.com coupon code isn't working, several steps can be taken. First, ensure that the code has been entered correctly, without any extra spaces or characters. Second, check the expiry date of the coupon, as it may no longer be valid. Third, some coupons are applicable only to certain products or categories, so make sure the items in the cart are eligible for the discount. Fourth, there might be a minimum purchase requirement to apply the coupon. Lastly, if all else fails, reaching out to Global Star Beauty's customer service might be helpful. They can provide assistance and possibly offer a solution. Remember, each coupon may have its own terms and conditions, so it's important to read them carefully.