I can certainly help take a look if it comes to that, but first, you may want to contact your hosting company and see if they even allow these directives to be set via .htaccess Some only allow .htaccess files to be used for password protecting directories, a few ignore them entirely

Also you say you entered the 3 additional lines, but did you try un-commenting one of them, testing, moving on to the next? In .htaccess file, any line starting with # is ignored, so it may be necessary to "toggle" the commented/ignored lines in order to find the syntax your server likes. You'll need to be careful and ensure that only one of the lines is un-commented at a time and through trial and error see which one works.

In a perfect world your host would of tested the script and edited their installation .htaccess copy so it runs out of the box on their servers.