Cognizant Technology Solutions India Private Limited - Unprofessional Conduct

I was interviewed by Cognizant on **th September'** after which I was told that I have been successful in the role of 'Associate'. After a few days I was submit my documents to an onboarding portal for my BGV. The exhaustive list of documents included all experience letters, ID proofs and address proofs. This was all given to them at least * weeks back. I submitted my resignation in my current organization with a notice period of ** days. My notice period ended on *th Jan'** and I was supposed to start with Cognizant on *th Jan'**. Just an evening before my joining and after completion of my notice period I was told that they couldn't hire me because the BGV came negative because I worked in an organization * years back that was blacklisted. I can't understand what were they doing with all these documents in the last * weeks plus. Why were they waiting an evening before my joining especially when I have completed my notice period to leave me high and dry without a job. This is an utter unprofessional behavior from a company. To top it all no one cares to pick up a call to talk on the phone and show classic unethical ways of blaming everyone else. This whole situation has left me jobless and well and truly Cognizant is to be blamed.