ds-260 approved then refused

[Tatka1222 0]

Hi all. my father (the beneficiary) had an immigrant visa (ds-260) interview on August 11th in Armenia. The interviewing officer told him his application was approved and all documents were in place. He gave him a pink sheet of paper with a congratulatory message and instructions to register for the courier service so they can send him his passport. It has been almost 6 weeks and we have not heard of them. I have been checking his status by his case number on CEAS website and it was showing READY FOR INTERVIEW up until Sept 19th. On that day the status changed to REFUSED. We have not gotten any explanation from the embassy. They do not speak to us over the phone and keep telling us to email them. We have sent 5 emails and have not heard a response. NVC keeps telling me that they are showing AP on their end and all we need to do is wait. How long??? Is it possible to refuse the visa after the approval on the interview? Is it possible that there is a glitch and the website status is incorrect? I need answers. Please help. Thank you.