djnickolas on "Can't get themes front pages to work"

Hello, i recently purchased Gem Pro Theme. I work at my site pages, until from no reason, i found out that my front page is blank. Yes it is a static page, default template, etc. But it doesn't show the default theme's content, it only shows what i post in that page. I tried to change themes, to see if the problem is only with Gem Theme, but the problem is in every theme. I don't know what to do, i' ve searched everything all over inteet, and i didn't find a solution.

Here is my site:
http://mokos-cars.gr/

Any suggestions?