Callback Campaign emails

[Doozer]

It's such a bizarre system. It says they get sent out once a day, but it can sometimes take over a week? Why can't it be done automatically? Is it a sole person's responsibility to send out all of these emails one by one or something? I wanted the gold chocobo feathers for a mount I've wanted for a while, but honestly it's not really worth waiting a whole extra week to be able to play (since we agreed to only play the new content together).

UPDATE: My partner received his email while I was typing this. For anyone who ends up here looking for answers like I did, I sent one invite on Sunday night, then impatiently sent another on Monday night, and he received an invite very very early on Tuesday morning.