HTTPS help

Hello,

can somebody help me with https problem? The thing is, with command site:mako.hr, I see Google for some reason index https version while site don't use https. Also, https links have title and description from another site hosted on same server.

I cannot figure out why this happening. On same server there are one or two web sites that use https, but all others sites are fine when I check them with site command.

I did try to put in .htaccess this:
but then I got this message when try to open site: Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

Also, can this be related to problem with situation where I'm trying to get better website rank for key phrase "radna i zaštitna odjeća" on google.hr and when i enter that phrase, result is on third page but shows up not completly related sub page. The thing is, when i enter" radna i zaštitna" only without odjeća, website is than on second page with three results. Same web page is in question (goo.gl/sjgpmM).

I hope that someone understand what I'm saying and any help would be nice.