Perhaps you are getting to the wrong page on the website. Type www.britishairways.com in the address line. That should take you (as of this evening) to a page that has a lot of ads on it- such as "Europe on Sale- Fly to Europe for $199". Click on the tab on the top right that says Executive Club. That should bring you to a page near the top of which is a yellow box with your e-voucher showing.

Mine posted 1 day after I spent $30,000. Did not have to wait for the month end statement or anything. If it's not there, maybe you ought to call Chase and verify that you did indeed spend $30,000 (excluding any credits and excluding the annual fee) before December 31st.