Problem with XMLRPC.php and can't insert media in to the posts

Hi!
I have some troubles with my website since I updated to WP-3.8

Recently I discovered a little bit of text jest on top of my website ( https://www.wdrodzedo.pl

fn() ?>() ?>ks ?>

After few days when I tried to open my page I had an error instead stating that there is an eroor in one of the lines and there was a path to the file. It was one of the Jetpack files. Considering I wasn’t able to log in to the WP Admin I went to the FTP and just deleted Jetpack files from my server. My website is working so I was happy.

Than I tried to install Jetpack again, and I did from the WP Admin Panel, but I can’t connect it with the WordPress.com account. When I go to the plugin page there is this message waiting for me

Your Jetpack has a glitch. Something went wrong that’s never supposed to happen. Guess you’re just lucky: xml_rpc-32700
Try connecting again. Error Details: The Jetpack server could not communicate with your site’s XML-RPC URL. Please check to make sure https://wdrodzedo.pl/xmlrpc.php is working properly. It should show ‘XML?RPC server accepts POST requests only.’ on a line by itself when viewed in a browser and should not have any blank links or extra output anywhere.

And so I went to the xmlrpc.php and it’s not blank, instead it shows up

fn()
?>()

?>ks

?>XML-RPC server accepts POST requests only.

So I also found the source of this funny bit of text on the top of my site.

So the question is if anyone know how to repair xmlrpc.php or know how to deal with that problem?

I also can’t paste any media into my posts. I can upload media, but it doesn’t show up when i press ‘insert media’ while editing posts. The media physically exists because I checked on the FTP server, and when I go to Media -> Library I can see it, but not in post edit page.

I don’t have any installed plugins at the moment, only Jetpack, but I checked that with Jetpack turned off as well. The Inster Media works when i swap to 2014 theme, but not in Parabola which I use, but it used to work a while ago (when I posted my last post).