It's obviously that these are just spammers under the guise of anti-spammers. I certainly wouldn't trust any product a spammer is pushing, especially not one that supposedly stops spam.
My company installed some spam-filter a few months back. Ever since that, I noticed a huge jump in amount of spam mails I received every day. The company finally figured it out and took it offline but the damage is already done. Unlike my personally email accounts, it's almost not possible to change work email address.
