Internet recovery threw me back to OS X Mavericks cannot download newest compatible OS

I HAVE a 15" 2013 MacBook Pro. internet recovery threw me back to OSXMAVERICKS. I cannot open the apple support page to download the newest compatible version of os safari keeps throwing a "cannot establish a secure connection. no other website is doing this. at this point the laptop is basically useless I've tried downloading on another Mac to a usb and transferring it that way but once I plug it into the problem Mac it won't let me open it. I need help