Exchange Online Protection (EOP) is the anti-spam service that is provided with Office 365. 

EOP sends an email once daily with a summary of messages that were flagged as spam from the previous day as shown in the image below.


If EOP incorrectly flags a message as spam, you can click the "Release to Inbox" link next to the message you want to release.


If a message that you would like to receive is regularly flagged as spam, you can click the 'Report as Not Junk" link to prevent it from being flagged as spam in the future.