Just got this message from Admin in the AH Forum from Blizz
Hello.
We’d like to clarify that nothing has been lost as a result of this issue. This is an issue with mail delivery, and we’re working to fix it. We currently expect that the fix is going to take a few days.
During that time, the mail you can’t see is not subject to 30 days expiry. It will only begin counting down from 30 days once we’ve fixed it so that you can see it and interact with it in your inbox.