You can view the emails that your web store sends to users via the Dashboard.
Go to ERP Integration > Site Logs.
Ensure the dropdown box in the top-right is set to Mail Log. If your site is still on Sync 1, then the Replication Log is shown by default.
If the emails are logged here and your customers are not receiving emails, verify that your domain has an SPF record set that authorizes commercebuild to send emails on its behalf.