Why do you need to connect to Wordpress.com? there is absolutely nothing on that site apart from downloading the core package, themes,, widgets and the WP forums.
Upgrades and updates don't use wordpress.com.
Have you tried going to that site with your browser to see if there is something in the hosts file blocking that site?
How and when did you know that your site can't connect to wordpress.com?
Incidentally, if your webhost has done anything wrong then we can't help you here. You need to contact them to correct their side. Don't you think this is quite logical?