May you explain this (I-824)

My I-824 was approved and my case is processing at Guangzhou. I am applying consulate processing (EB-2). Today, I received an email below. May anybody explain what this email mean? Is this related to "QUOTA" issue? I did not request any information after this case was approved.

Thanks in advance.

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On September 15, 2005, we responded to your request for more information concerning your case. If you have not received our response within 30 days from this date, please call customer service at 1-800-375-5283.