今天收到從未見過的notice (I-797C), 急請各位指教

今天收到從未見過的485 notice, 急請各位指教
" After review, we have reopened the above application or petition, or reconsidered the decision previously issued. You will receive a notice under separate cover once all action has been completed"

Meanwile On-line updated:
"Current Status:

On November 2, 2006, we mailed a notice requesting additional evidence or information in this case. The notice explains in detail what additional material is needed. If you have questions about the notice, what is required, or if 30 days have passed and you have not received the notice. Please contact the service center where you ted your application during business hours
"
They are requesting me more evdience on line, but the notice letter only said" they reopened my case"


help, please.