You should be able to get to the message from your Tax Expert by logging into your TurboTax account and clicking the red box that says "EXPERT HELP" in the upper right-hand corner of your screen. Next, in the window that appears, look for "my contact history" and click on it. In the message(s) that appear, click on them and you should see the message you are looking for.
Or, look for the bell icon in TurboTax Online to see if you have Notifications (screenshot below):