Try reset the phone. Not the modem and router but the phone. You have to make sure that it is registered with green.
On the phone, press menu and search for reset phone (if i can remember correctly)

It happen to me when i request to change my voip number. Just a simple configuration they took more than 1 month plus to have my voip working.

Sorry, just saw your message.

Yes you cant find it on the button. Look for the menu button where there are phonebook, bla, bla...
Then you try look for "phone" option. Press left or right button. Explore by pressing "ok" button.
If not, get the manual book out for look for the "reset" option.

Happy exploring

This post has been edited by jerrycyk: Sep 5 2012, 10:31 PM