I saw a premium domain listed for sale at $60 and went to grab it.. and when I tried to add it, it wouldn't let me. I emailed them and they said it was already

I saw a premium domain listed for sale at $60 and went to grab it.. and when I tried to add it, it wouldn't let me. I emailed them and they said it was already taken. So why advertise a domain that is already taken? Definitely annoying.