Is my account in a sort of trial or is just was banned long time ago? 
Thanks!
My account is already linked to my Xbox One and my email is linked to the battle net account 
Logout/login? Try reconnecting it? Otherwise you may need to contact Customer Support.
Yeah I tried that with 3 different web browsers.
Probably time for a ticket to get it sorted.
Oh! and how can get a ticket?
Click Support in the top right corner of this or any forum page, choose Overwatch, and just follow through the steps to open one.