On Yahoo Mail, I can no longer search very old email information. How can I fix this?

If I wanted old quotes sent to me in very old emails, I just had to recall a few words from them, search those words in my yahoo mail, and yahoo mail would find my old email with the quotes. Now the search comes up empty. Can I upgrade, or something, to get this old service back?|||I had same issue. So I chatted with Yahoo customer service (http://help.yahoo.com/l/us/yahoo/mail/ya鈥?/a> The agent looked at my account, acknowledged the issue, did something (I have no idea what), and then told me to wait 24 hours before logging on again. I did, and it worked! He said that if it happens again, I should chat with their customer support again.