Blocked by msn.com MX, contact for MSN.COM postmaster ?

I found out that our outgoing SMTP servers have been blocked by the msn.com MXes. In a nasty way, too -- no SMTP error, the TCP connection is simply closed by them immidiately after establishing it. We're not listed on any RBL/DNSBL and have an active abuse desk. I mailed postmaster@msn.com, msnhst@msn.com, noc@microsoft.com, but didn't get a reply from any of them. Does anyone here know who to talk to ? Thanks, Mike. -- Anyone who is capable of getting themselves made President should on no account be allowed to do the job -- Douglas Adams.