It is relatively simple:
Make your return or exchange request in your account using your order number.
Print the order confirmation email and insert it into your package.
Attach your return slip to your package.
Drop off your package at the nearest post office.
Follow your package to know its progress anytime.
The return shipping costs are free in case of damage or non-conformity of the product received within 14 days.
You are responsible for the return shipping costs in case of a refund or an exchange, which are the same as the shipping costs you paid beforehand.