How do I make sure someone stays permanently offline on Yahoo chat?

For years I was able to put people permanently offline before deleting them from my friend's list and i never had to worry about them again. On the new program this feature is a nightmare. People I haven't talked to in years are commenting on my profile pic or sending messages. Apparently all of them see me back online even though I didn't change their status. When I went into the status feature, I realized that even after I went through every name in my address book and switched them to permanently offline, the very next time I signed in it switched them all back to available. If I delete them from my contact list do they still have access to my account as I haven't completely deleted them from that. It seems that I can do all I want but until they delete me from their llists they have all the control. I feel like I have no privacy what-so-ever once I accept them as a friend. Ironically, people still in my friend's list remain offline until I manually change it, but no one I removed from it.

Also, I access yahoo chat through my bb, my computer at work as the web-based version, and at home on the downloaded version. Is it possible that they are in some conflict with each other? Thank for your help.