Essentials chat isn't working for me at all. I even tried reseting config, still nothing.

Yes. Very well. Have you tried the following:

1. Turn the server off and on again
2. Make sure you have the EssentialsXChat plugin, then repeat step 1

If so, please http://pastebin.com your config.yml and pass us the link here. :)

I know, I reseted config, EssentialsXChat was installed and etc.
Turned out it was Factions who changed chat. Fake alarm I guess.
Thanks anyway.