B1/B2 Visitor Visa Refused

Hello all,
I applied for a B1/B2 visitor visa for my Dad at Mumbai consulate through Dropbox on March 08. It was showing as Application Received for close to 10 days. Then the status changed to Refused. It was showing that for 3-4 days. And now we have received the passport also without stamping. What is the next process that i should do? Not sure why the visa was refused. We did not receive any call or emails explaining the grounds for refusal. Greatly appreciate any guidance or help from the forum members. Thank you.
Have a good day.

Did your dad not receive 214(b) via email or mail? Are you sure you submitted all the required documents to dropbox appointment?

You may want to email the consulate or may want to reapply.

Thank you for your reply.
When the documents were submitted through dropbox, the VAC officer (Visa Application Center) asked for only the appointment confirmation, DS-160 page and the passport. My father did have the supporting documents with him, but the VAC officer did not want them. I was not sure why the officer did not want to take other documents though. My father already had a old US B1/B2 visa that was expired 5 years ago, not sure if this piece of info helps. Thanks again.

That doesn’t seem normal to me unless the policy changed for B2. Many times VAC people think they don’t need certain documents with visa application however I always tell people to insist on submitting any supporting documents, apart from the standard list, that can make your visa application strong.
I think you should call VFS and dicuss with them as well as email the consulate that returned the passport.

http://cdn.ustraveldocs.com/in/in-main-contactus.asp#contactinfo

Thank you for your kind guidance. I will do what you suggested and hope i get a response soon. Thanks again.