According to Modlily return policy, to return your order, you need to:
Log in "My Orders"
Click the Return Button beside the order you want to return/refund.
Modlily customer service will reach out to you on the ticket, and approve your application.
You will get the Return Address and RMA number in the ticket as soon as your application is approved.
Pack the items you want to return, and ship them back by FedEx, TNT, DHL, UPS. Post Office or any other shipping policy.