The (888) 652-2342 number worked for me to activate FrontPage 2003 in September 2017. However, there is a new wrinkle:

The phone recording offered to send the activation code to a smartphone; all you have to do is punch in your smartphone number. But what you get is not the activation code but a hyperlink. I went to the hyperlink, and it asked me to enter my 9-digit "Installation ID". I examined the activation dialog in FrontPage 2003 closely three times through and found no "Installation ID", nor any 9-digit number. Perhaps it used to be in the place where it now says that phone service is no longer supported. Anyway, the smartphone solution was a dead-end for me there, so I had to go back in and say no to that option. Then it worked fine the old way.