This has cropped up a few times of late.
You need to telnet into the router:
Administrator is the default user on the box.
You should get something similar to below after doing this.
------------------------------------------------------------------------
______ Thomson TG585 v7
___/_____/
/ / 7.4.20.3
_____/__ /
_/ /\_____/___ Copyright (c) 1999-2008, THOMSON
// / /
_______//_______/ / _/______
/ / / / / /
__/ / / / / / _\__
/ / / \_______/ / / / / /
/_/______/___________________/ /________/ /___/
___________ /
\_ / / \___/
/ / /
\_____/ / \________/
/__________/ /
_____ /_____/
/ / /___/
/____/ /
/___/
\____/
------------------------------------------------------------------------
_{Administrator}=>
connection unbind application=SIP port=5060
saveall <Enter>