It isn't clear whether to use a free service (like 
http://www.k7.net/ ) or a paid service. The paid service would be more stable, but the organization might not be able to afford a monthly charge. (And it looks like it can't.) I have signed up for a K7 account to give the service a try. The phone number is 206-202-2490. I've added the following message at the site.
Saluton! Welcome! You have reached the Esperanto Society for New England. For free information about Esperanto, the International Language, please leave your name and how to contact you: your phone-number, email, or postal address. Dankon!