Quite a while ago, we SH editors discovered that when we send a rejection to a cox.net address, cox considers the rejection to be spam, so they send us a bounce message and don't deliver the rejection. For those unfamiliar with it, cox.net is a fairly major ISP, covering at least 20 US states. Their slogan on their main tech support page is "Just like a true friend, Cox is here for you 24/7."
When we first encountered the problem, we attempted to talk with the cox.net support people to (a) convince them that these messages aren't spam, and (b) find out what about the messages was causing them to be marked as spam. We were informed that since we weren't cox.net subscribers, they wouldn't talk to us. At all.
We eventually figured out that if I re-send the rejection from my personal account (rather than using our usual semi-automated system), it goes through. But that's a (minor) pain, and sometimes it takes a while for me to get around to it.
A couple of cox.net subscribers who submit to us, and who had therefore received delayed rejections, pestered cox.net support about it, but never (as far as I know) got anywhere.
The bounce messages say that we can make our message go through by writing to email@example.com with subject line UNBLOCK. If you do that, you normally get an autoresponse from postmaster saying that if you're a customer, you should contact Customer Support.
I always try the UNBLOCK thing, but I don't think it actually does anything. But I've taken to sending the UNBLOCK request before sending the rejection, just in case that helps. Last month, for the first time, I got a query from firstname.lastname@example.org about an UNBLOCK request; I very briefly and very politely explained the situation to them, and never heard from them again.
So this evening I sent an UNBLOCK request and then a rejection. And in response to the UNBLOCK, I got back . . . a bounce from postmaster. Saying:
This Message was undeliverable due to the following reason:
The user(s) account is temporarily over quota.
Please reply to <Postmaster@cox.net>
if you feel this message to be in error.
There's a certain purity and elegance to how self-contained that is--it's like a recursive definition. I'm tempted to reply to postmaster letting them know that the postmaster account is over quota, just for the fun of it.
Anyway. I guess my real point here is that if you're a cox.net customer and you submit to SH and you want a timely response, you may be best off getting a non-cox email account and submitting from that account.
If you submit from a cox account, you'll still receive a response from us; it just may take a while longer to reach you. Apologies; if I knew how to fix that, I would.
Oh, and if you happen to know anyone who works at cox, could you mention to them that their postmaster account is over quota?