I can think of 3 things in the system already that can help in this situation.
1) You can set the "Carbon-copy e-mail address" config option. You could put it to some email account only used for this purposes that you don't normally check. Forward back an email to a user from it if they need it re-sent.
2) The e-mail log in the Admin Zone provides some debugging help.
3) The dispatch email is sent from the add note screen. It just so happens that doing a dispatch prepopulates a note, but you can add an identical note (or something closely similar) manually.
I can think of 3 things in the system already that can help in this situation.
1) You can set the "Carbon-copy e-mail address" config option. You could put it to some email account only used for this purposes that you don't normally check. Forward back an email to a user from it if they need it re-sent.
2) The e-mail log in the Admin Zone provides some debugging help.
3) The dispatch email is sent from the add note screen. It just so happens that doing a dispatch prepopulates a note, but you can add an identical note (or something closely similar) manually.