contact mode for H1b dropbox visa stamping Administrative Processing 221g

Hi All, Here is my timeline Documents Submission: 19th December, 2016 Case Creation: 20th December, 2016 Status Update: Administrative Processing 221g on 27th December Today, I have received the notification from the US consulate Mumbai that my application is pending under section 221g and it might take further time to process it. My questions are as follows: 1) Do I require to submit further documents or is it just a delayed procedure? 2) How will I get the 221g notification (to submit additional documents), by email or by post? I have my flight scheduled to US on 9th Jan. it would be great if anyone dealing with similar case wants to chat . thanks, Shivam