I have had the same issue for some time now and have posted a similar thread. I have been unable to resolve it as marking it as non spam does not work. The next time I recieve a message from the same source its marked as spam again! In the end I switched off the spam filter altogether and manage it manually. I am now in the process of moving over to another provider. That will take a while as this has been my main email contact address for years!
I am getting 100s of spam mail a week with some of my normal emails mixed in with them. It's very time consuming and frustrating sorting it all out. All the more frustrating as I don't have a lot of genuine email traffic really :-(
