Mail problem

In Mail I did a large bulk mailing and it timed out. I usually break it up into quarters, but didn't this time. Now I'm stuck on the screen with the "Cannot Send" message and the large list of recipients. The buttons to Try Again With Selected Server, Try Again and Edit Message are off the bottom of the screen with no way to get to them, so I cannot get to them through scrolling or any other means that I know of to at least edit the message. Because of this problem I cannot quit Mail or shut down the computer by normal means. Forcing it to shut down does not close the Mail program nor delete the message. Help!