Hi Fernan07,
Thank you for reaching Microsoft Community.
The shipping label should be sent to your email as an attachment on one of the system generated email. The shipping label is also available to print online. Here is how to find it: Check the status of a Surface repair order, cancel the order, or print a shipping label - Microsoft Support.
If needed, please contact support for us to check on the order and have the label sent. You may contact them through the number listed on this page: Global Customer Service phone numbers (microsoft.com) or through this page: Contact Us - Microsoft Support using the details we provided on this thread: Contact Support.