Thank you for reaching out to us. We are sorry that you haven’t been able to block certain contacts. We are considering bringing this ability to outlook on the mobile browser. However in the meantime you can do this from outlook.com on a desktop or a laptop. Follow the steps mentioned here https://answers.microsoft.com/en-us/outlook_com/forum/all/how-do-i-block-the-email-of-someone-harassing-me/d2d4a775-b8c8-4c38-bcc6-404a940030e8.
An error occurred while saving the commentDaniel commented
Make it to where you can completely block emails not sending them to the junk folder make it to where you select emails press block you never see them again I’ve had to go through hundreds of junk mail that I blocked just to find one email that I was missing. If someone is the blocked then you should not get any emails from them in any folder not even the junk folder