Been a while since my last post. I've had a weird exception that causes the WCF service proxy not to respond after a certain time (10 mins I guess), so thanks to this post I figured out the solution.
Solution that worked for me was to enable reliable session on the client application's config file and service host's config like this:
<reliableSession enabled="true" inactivityTimeout="00:20:00" />
and that lead to increase from 10 mins to 20 hours :)