HCL Technologies — hcl not releasing offer

I attend interview for hcl for one of the oracle developer position in the month of september 2017. I got selected. They asked me to give all the documents.

After that they did not call me and given any update.

When i tried to call, they said they are working on my offer letter but did not give any offer.
I also cannot understand about this strange interview.

Name of the hr : surya
Date : sep 2017
Loc : electronic city, bangalore