Our ARIN allocation is:
67.217.144.0/20
and SORBS had us listed within a larger black listed range, like the containing /12. It took us weeks to be removed from that range (or to have an exception added). This was probably a couple of years ago, or early last year.
Our experience with their DUHL was very similar, and around the same time. My post to NANOG about it is here: http://mailman.nanog.org/pipermail/nanog/2011-June/037568.html Despite the only public reply being utterly unhelpful, the post resulted in human contact from SORBs and an eventual resolution of the issue. I have observed this pattern repeated several times on-list since then (and several times prior to my post), so it would seem that posting to NANOG is (or, at that time, was) part of their delisting process. Nathan Eisenberg