Hello,
at http://www.libreoffice.org/get-help/mailing-lists/how-to-unsubscribe/ we have a nice and convenient documentation what to do in case unsubscription to one of the lists is unsuccessful.
I think it makes sense to have that page localized into various languages.
As soon as you have it localized, give postmaster@documentfoundation.org a ping, then we can add an appropriate footer to the local lists.
Do *not* reply to this mail, but rather ping postmaster@ directly.
Thanks,
Florian