Hopefully this is the right subforum, I'm not sure.

Anyway, my partner and I decided to come back to the game after being gone for about 6 months. A mutual friend was also planning to return, and said that one of their friends had sent them an email for the Callback Campaign and that we should wait so they could invite one of us. The only problem was that they hadn't received their email after a day or two (despite the site saying "Invitation e-mails will be sent once per day"). I didn't want us all to be waiting for that one email, so I just bought my sub (I don't really need the invitee items anyway) and invited my partner back. That was yesterday evening, and he still hasn't received his invite.

I know I sound impatient, but I'm mainly looking for info from people who have successfully sent and received these invites. Do they actually get sent out once a day, or once a week like I've seen some people on Reddit say?