I've telnet'd into the server to check my email with Pine. I don't use mailing lists, but couldn't you use any email program to send to the list? (Like Pine?) I wouldn't think you could add "users" to a list or remove from list without control panel, but again, I don't use lists. But I'd think you could still use the existing list by emailing with Pine.
If you have never used Pine and have telnet access with your plan, post back here and I'll try and help.
Also, post if you're using a PC or Mac. (With a PC I can tell you precisely; with a Mac I'd have to describe it generically cuz I don't know Mac telnet, etc.) But once you got telnet'd in, the commands would be the same in Pine.
p.s., Still down as of 12:15 p.m. EST.