Cox was doing something similar. After several complaints, from me and others, they apparently turned this off on my account.
I use Thunderbird, and it's already trained to distinguish spam from non-spam. On a T-bird forum, you might ask where this data is kept. Then, see if there's a way to upload it to Yahoo's webmail.
Save yourself the trouble of calling Yahoo's "Premium Phone support," in my experience you're likely to wait for an hour or more to speak with an agent, and when you do, the agent will be ignorant of all but the most elementary aspects of email, computers, and Yahoo's web app. I recommend that, instead, you look for a Yahoo forum that might have a thread discussing how to control Yahoo's arrogant spam "protection."
