Hello I'm encountering the very same problem but I did not understand how to solve it.
As soon as I opened a single article in the category "About us" and saved it the icon disappeared. I would like to use them in that nice module...
Where the hell those bloody icons are set?
Why all the demo settings are so esotheric and arcane? It's frustrating...
Thanks
EDIT: ok now I can see how it works... it's the bloody TinyEditor that erases the icon codes.... arghhhh!!! You have to open the articles only with codemirror... :-( not very convenient...
EDIT#2: I was wondering where to find other icons to use; the answer is this file: fonts/Flaticon/css/Flaticon.css in the template folder.
Why in this template aren't there any typography or icon page like are in other templates? :-(