I'm slowly remembering why I stopped putting skill points into hireling emails. I'm not really a fan of how they work when you get 2 packages a day. Since the mail is completely dependent on the mail reloading, if you don't change zones, you don't get the package. This is especially an issue with Cyrodiil right now, since without leaving or going to the Imperial City, you won't trigger your mail. And due to the queues to get back to Cyrodiil, it makes it even more difficult to get these hireling deliveries. The time stamp to get your second package is 12 hours from the time you get them in your mail inbox, so it's pretty important to line these up if you want 2 a day. Missing a package due to failure to load is not something that the player can always control if they want to stick to a specific area. This seems like very poor game design, since the user isn't necessarily doing anything wrong.
I suggest having a way to set the timers on the deliveries and just have them delivered at those times. You'd still need to be in game for it to happen, so no one could just wrack up materials. But I should be able to set them at a time so they can always arrive as long as I meet the requirements (in-game, able to get mail, have the skill, etc).