NON-Live Messaging from User's Account on our Shopify store

Hi-

I’m striking out with Shopify customer support and can’t seem to find a solution to a feature I feel like may be a pretty common feature request.

We are looking for a way to have a message portal within a customer’s account that would allow for back and forth communication. We are not looking for a live chat/pop up box that would lead the user to think they should receive a response in real time.

Is there an app that ties into the user account dashboard on a Shopify store that allows for messaging over time?