Visibility of DMARC reports
At present DMARC reports are not visible under Security & Compliance.
DMARC reports will help to determine the messages that were allowed through or rejected.
rua feature will provision mail delivery notifications but will not provide full details of message delivery status in a tabular format.
Microsoft should be leading the way on Email security!
Please include an automatic "dmarc@your365domain" address with Exchange Online to receive reports from inbox providers and a reporting interface in the Admin Centre.