Mailed our passports to Chicago Consulate on 11/20 and some really inept people at the Chicago Consulate refused my package on 11/23 (as seen on the delivery confirmation tracking website).
I had clearly written with Bold typeface "FOR OCI COLLECTION" on the front and back of the envelope, so they do not confuse it with new OCI application.
I guess they are beyond any hope as far their efficiency is concerned. Now, I plan to go down to the office in person to get my OCI.
Note: I have yet to get my passports back from USPS. For some reason it is showing that Chicago USPS processed it today 11/29 for returning the refused mail.