A suspended mailbox and all of the information on it including the data, will not be deleted or dropped. However, the following actions are taken:
Users on the mailbox will all be suspended so they will be unable to access the mailbox, whether through the portal, API, or FTP/SFTP.
Inbound data flow from both directions will still be effective, however, outbound data will be disabled.
NetworkAdmins can unsuspend a mailbox at their discretion. No data will be automatically sent or resent. Customers will be responsible for determining what data needs to be sent/received.