Same things happened to me.
EW support is available from 9am-6pm Monday to Friday (USA-PST).
They will deposite an Opus engine license to your account within 48 hours.
EW support message:
"In the Installation Center, please activate the license.
Then proceed to download the Opus engine and the Product Support installer, which you will find at the top.
The Hollywood Backup Singers library will then have a download button next to it."