回複：EAD renewal news (NSC) - I think it is true.

I actually did a research on your case. Below is the quote from the INSTRUCTIONS of the Form I-9 (Rev. 05/31/05) - Employment Eligibility Verification (OMB No. 1615-0047, Expires 03/31/07):

"... If employees are authorized to work but are unable to present the required documents within three business days, they must present a receipt for the application of the document(s) within three business days and the actual document(s) within ninety (90) days."

Therefore what USCIS informed you was correct. You can present the receipt for renewing your EAD and the actual EAD in 90 days.