Hi Mohammad,
Thanks for your review! It seems you ordered the Rose Gold mesh strap for the Avalon & Maverick collections, so it won't fit the Milan collection as they have different dimensions. The product page states what collections the strap is compatible with, but we're sorry if this wasn't 100% clear.
Regarding a return, we offer a 30-day hassle-free process via our simplified returns portal available here:
US Returns: https://returns.ralphchristian.com/
Int'l Returns: https://ralphchristian.com/pages/international-returns-portal
Simply input your order details and follow the instructions. Please feel free to reach out if you have any questions and we'll be happy to assist.