Cognizant — hr not leaving to onboard even after having the offer letter

Hi i have attended interview in cognizant on nov 2017 and got offer letter on jan 2018 and my doj was april 2018 but my onboarding pass not generated till eod on doj they assured and asked to relived from the company and they will generate and provide the on boarding pass and get onboarded the next day itself but till now they have released 3 offer letters of different date and still not leaving me to get onboarded.5month they took to complete the bgv and after getting relived now they are saying bgv not cleared as one of my company closed 7 years back itself and dnt have any details apart from offer letter resignation letter and salary slips. Not sure wat they are still looking when other companies have accepted it.

They made me to resign from the company and now they are not even leaving me to get on boarded on cognizant also.

Now no one is responding to the calls nor mail.

Request to please help.