On the mail servers I set up in our company, I use several blacklists in postfix. These really help take care of the spam we get send our way.
But every once in a while one of our (potential) customers can't send us mails because they are on such a blacklist. And it usually isn't a false-positive. They sometimes share mail servers with other companies on a server by some hosting company. Or they send out particularly large amounts of "newsletters".
While this happens rarely, when it happens, it's very hard to deal with. Because obviously the problem is our mail server. As they have no problem sending mail to other people. I usually tell our people that I won't change our perfectly fine config to allow people with messed up email servers (or ethics) to send us mail.
Referring these people to removal request pages of the RBL is pointless either. These are usually people in marketing who have no clue what I'm talking about (and don't care for it either).
But that still leaves me with the problem that we would like to be able to receive mail from them.
How do you handle a situation like that in your company?