Check settings again (and read extra instructions below options you enable), check the local Font Awesome path again, check if you're setting the right style, press CTRL+F5 to refresh your forum (or clear browser cache too; if you're using Cloudflare you might need to wait a bit more).
Otherwise pm me at least your forum url.
Not sure what problem you have. Maybe the fix for FlatAwesome style will fix this (check FAQ at the bottom:
[cXF] Conversation Button under Avatar). For more help I will need admin access to see what is going on.