sabotoge by former board members

Ed, I have to admit I have no idea what your problem is.

A former member "owns" an "email service"?

Do you mean that a former member has passwords and user access to the email account for the organization?

When you say that your email correspondence is being "leaked" to homeowners, do you mean that someone is forwarding copies of the organization's emails to ALL homeowners or to specific homeowners?

I would think that as president you would not necessarily need to call a special meeting to close anything down.

You have discovered potentially illegal activities associated with your email account.

I would close it immediately and contact all current board members with an alternate email account (you can get one free from AOL, Yahoo, Google, and many other places) and let them know what has happened and that they are not to use the previous email account.

I am also very confused by your other issue.

Why do you have to keep asking for email addresses of homeowners from 2 board members? If you have sent them emails in the past, you should already have those.

Are you saying or implying that 2 current board members are part of some conspiracy with the former board member who is hacking into your organization's email account? And that they are withholding financial information?

the multiple administrators to the web email.. are your issue.. change your service.

Steve,
If the question is can the President take this action, if he feels there is some leak of confidential material, I would think the answer is "yes" as Michele says. However, why not canvas the board by phone and explain your concern and ask for feedback from other BOD's. If you can't get verbal or e-mail agreement, start the process of hiring a new service at the next BOD meeting. If a former Board member has an e-mail list of members, it would all depend on how he accumulated the list. If he amassed the list using his position as a member of the board, I would believe that mailing list in association property. However, many time these e-mail blasts are sent out with no attempt to really hide the addressees. Search some e-mail from this company and see if there is a way you can pick out and collect individual addresses.
If on a list you can get to, it is public info. How many times do we see e-mails with long lists of names and e-mail addresses in the format. Our association has 65 units, all but 4 have e-mail accounts and are on list. Others are notified by snail mail or delivery.

Jim, Who is authorized to shut down the service? I think the OP said he was a Board member. I expect he would have no authority to break a contract or put a new one in place.

Mary,
I agree. THE Board does have authority, a single Board member doesn't.