Hotmail/MSN postmaster contacts?

["Weier, Paul" <paul () ibsys com>]

Any Hotmail/MSN/Live postmasters around?
 
My company sends subscription-based news emails -- which go to thousands of users within Hotmail/MSN/Live.   I appear 
to be getting blocked recently after years of success.
 
I have read the postmaster doco at MSN.  I have put SPFs for SenderID into many of my news station domains but it 
doesn't seem to be affecting my success at delivery over other domains which do not yet have any such configs.   What 
am I missing to get un"blacklisted"?  I can't seem to find any human contact info on there.
 
Any offline contact would be greatly appreciated.
 
Apologies for the noise.

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Paul Weier                                 paul () ibsys com