Asking for a return
Sign in and open the order. Once it shows as delivered, the order page has a return form. You have 7 days from delivery to send it, and the order page shows the last day.
Each order gets one request, and it covers the whole order. Pick the item with the problem, and if there's more than one, describe the rest in the same message.
Updates on your request appear on the order page, because there's no email address on your account.
Refunds
Refunds are paid in crypto. Each one is approved and sent by a person. The website itself can't send money.