Based on my experiences with the (terrible) Craigslist spam ghosting algo, attempting to get help for that over the random junk I was legitimately trying to sell which got me ghosted, and then doing a lot of research on similar problems had by other users...
...which led me to reading about Craigslist's history of "litigation over innovation" and the (inevitable and correct) complaining about how terrible every /other/ part of the site is...
...and the attempts to talk to Craigslist about such problems by users and litigation targets, all lead me to believe that attempting to communicate with Craigslist in any way is like talking to a particularly recalcitrant wall. They do not care. Sadly their US monopoly position makes it easy for them to act like bad netizens, and they do. Since the classified market is basically free under them, they're like the Windows monopoly. Nobody else can get a fair shake to take them down, even though a lot of people dream of it.
Best of luck. :(
I actually think there's lots of oppurtunity here, with many online services actually... to win by doing things better in a way that serves the users, not primarily the company. There's money in that. re CL: Afaik there's no patent or trademark on classifieds or 'community' moderation. You could win simply by doing that, not pissing off your users by ghosting (aka stating why your rejection happened), and say umm not silently dropping in/out bound mail, and not trying to play nanny mail relay. Non agnostic or faulty delivery liability anyone? By the way, did you know CL has and does archive every post (and quite probably every image and email) since inception in MongoDB? Want to know their reason? Supposed regulatory compliance and 'Oh, our users might want to repost an ad'. Really? From a month ago, a year ago, ten years ago? Bullshit. They're needless data whores acting against you. Anyway, that's off Tor topic. But I will restate my request for blocking policy/implementation info, rationale, and discussion, for any internet service really, whether on or off list.