To initiate a valid return, reach out to the brand owner by replying directly to your receipt email or by clicking on the Ask a question or Contact shop button on any product page. Read more about how to contact a shop here.
You can find a shop's Terms & Conditions and Return Policy by clicking the Policies tab on their brand page at Tictail.com. You can also find return policies on individual product pages, under the Shipping and policies section.
Once an order has been placed, you can also find the shop's Return Policy in your email receipt.