.htaccess is wrong

Hi!

I had a normal .htaccess file.. i did upload quite a lot of plugins today, including w3tc so it became a bit longer than the normal one..

So today i did paste some bit into it (guided by http://www.webdevdoor.com/wordpress/improve-wordpress-website-page-speed/ ) via SEO plugin by Yoast and got an internal error. So i deleted a new bit, left the normal .htaccess file as i thought and still get an internal error.

My website is not running, i do not have initial .htaccess file.

I called my hosting providers and they suggested to rename my file as disabled. Now website is running but they said to correct that mistake.

So i do not know how to access and what to do at all!

Please, help!