My ISP blocked port 5060 too,
But every other ports is avaible.
A service like
www.pbxes.com made ports 80-5060-5061 avaible to connect, and a lot of people use it only for this reason.
And i'm able to connect on port 5061 with my sip phone without any problem.
Voxalot is easier to use, is very fast but i cannot communicate with it, so is possible to open another port here at Voxalot....only one port and all my voip problem with my isp would be resolved.