About the digital download and CD key

Hello everyone,

I just bought delta force xtreme 2 digital version online.
And I got a confirmation e-mail that I've purchased the product.
It tells me to log in novaworld -> my service to download it,
however when I logged in, the website writes I have to enter CD key to continue, or I can't use any service.
But I didn't get any CD keys in the confirmation e-mail...
So I can't proceed to the next step.
I am stuck on the page requiring me to enter CD key.
What can I do for it?
I tried to contact Novaworld, but no one is answering...
Do anyway know what can I do or whom to ask for help?
like how to contact Novalogic customer service?
Thank you so much

Jack