The best way to ensure your PSAs and CSAs are receiving your emails is to use the mailer. This of course sends them to their SFI mailbox so if they are not logging in to their account they will not see them.
For those that have confirmed their email addresses you can also use the mail system you use normally to send out emails.
There is no guarantee that your messages will be read by the recipient but at least you will know they have been sent to the correct email addresses.
