This has only happened the last few messages I've supposed to have gotten. I'll get an email notification that I have a new private message, then I go to the private messages section of my account only to see no new message. My inbox was only listed as 15% full (just cleared it down to 6%), so it's not overflowing.

Is there some reason the messages would vanish? The sender of the message (as listed in the notification email) has confirmed that I should have received a message during the back-and-forth.

Sorry for the inconvenience and thank you in advance for the support.