If email from a blocked sender still appears in your inbox, the sender might be hiding their real email address. This could be for legitimate reasons, such as wanting replies to go to a different mailbox.
How to check a sender's real email address
Select or at the top of the message window and select View message source.
Scroll down the Message source until you find the From field.
Highlight the email address enclosed within < > and right-click to Copy.
Use this real email address to block the sender. Read how to Block senders or unblock senders in Outlook.com.