going back further, I found http://lists.wikimedia.org/pipermail/wikiversity-l/2012-February/000866.html
so Harry has been trying to unsubscribe since February. I looked back another year and found nothing.
(It's pretty common on mailing lists to see posts to the list requesting unsubscription. That is, it's common that people don't follow instructions. When someone writes, saying that they have tried to unsubscribe, but it didn't work, and giving exactly what they saw and what happened, usually anyone can help. But when all the person does is to start yelling STOP!, while giving no information, most people ignore it. Funny how that works.)
Jeffrey Peters mentioned Phillipe as the manager of WMF lists, but didn't give the email address.
Philippe Beaudette pbeaudette at wikimedia.org
is from a mail in the list archive. Personally, I'd rather solve the core problem, lack of active list administration, rather than bother Philippe over a small problem. But I suppose it's reasonable.
Normally, to handle obtaining new list moderators, see http://meta.wikimedia.org/wiki/Mailing_lists#List_administration
I've years of experience administering mailing lists, serving community consensus, and this is a very low-traffic job, I've seen nothing for a long time that would have required an administrator, except for these unsubscription requests.
But admins should be watching the list, as I have for years.
However, I'm blocked on Wikiversity, so I can see that some might think it a bit weird for me to volunteer...
Erkan Yilmaz is trusted, how about him?