USA F4 Family based immigrant Visa

My Family is running with F4 Family based immigrants Visa process. Submitted Petition has been approved in May, 2010 and NVC number has been received June,2010. As Step 2(NVC Processing) Petitioner and applicant have been submitted their supports to NVC, but we haven’t been received any Invoice number / case number yet, which we need to use for pay fees.
Is there anyone advice on these what we are lacking ? Kindly please advice petitioner and applicant document check list which needs to submit NVC under NVC processing.

Your earliest support and response will be highly appreciated.

Best Regards,
Vishal Patel
Whatsapp: ±61-410133456