W-9 Tax form for Government Agencies

I work for a US Government agency and have sent several emails requesting a W-9 form so we can take care of billing on our end. How can I get this form from you and why have my emails gone unanswered?

Hi Chad,

We already replied you via email.
Please check your email box for more information.
If you have any other concerns, feel free to contact us.

Regards,
Huyen