We are having a very similar problem with my wife's email.
She uses Win7Pro and Outlook 2007. About 5 days ago she suddenly stopped receiving messages into her inbox. Messages are sent from Outlook with no problems, they just are not delivered to her inbox. If she uses the 'web mail' application she can see there are messages waiting to be downloaded. All of the recent security changes (SSL and port numbers) we made back in January. My email continues to work fine. Her settings are exactly the same as mine.
1) I ran 'scanpst.exe' on her PST file, and it found some errors. These were reportedly successfully repaired; no change
2) I built a brand new PST file on her machine; no change
3) I added her account to my PC/Outlook (which works fine for my email); her incoming messages are NOT downloaded, when messages to my email account are downloaded.
I've called COX tech support twice, and they continue to tell me 1) check your email settings or 2) it's a Microsoft problem. I think #3 above proves it is NOT a Microsoft problem, but rather something wrong in her email account at the server level.