updated theme does not display changes

I have being struggling with this problem for the last days.
On the Theme screen under Appearance, when I activate one of the installed themes, then click on visit Site(or my Site name) in the top toolbar, nothing change. The same old website displayed, regardless of witch theme I choose.
I tried to clear cache on my browsers, and called my host provider with no luck.
would you please provide any assistance, I will highly appreciate it.

My website is
http://www.sehatokom.com/