You can see this article, it might be useful for you:
How to Get Around It
The work around is connect to a VPN. A VPN bypasses the firewall, because after you make your initial connection (which your ISP can still deny) you have formed a private tunnel between your computer and your VPN’s server. So when you go to use Skype you’re not going through the firewall at all. You can basically do whatever you’d like.
Ways to Get a VPN
There are tons of websites that offer this service for free, and my best advice is to just try out a few and see if they’ll work where you are. Things change on a daily basis, so keep switching around if you hit a roadblock.