Cognizant — cognizant doesn't release offer letter after being selected in hr round.

I am more than 10 years exoerienced in IT industry. HR scheduled interview in one walk-in interview and i cleared four rounds and got selected and I discussed salary component too and HR said it will take two weeks to receive offer letter. But after two weeks got email saying your offer is in hold. Then after one week i got another email for walkin and i asked whats my offer status. She forwarded to another hr and he said it's under process. Then after two weeks i got email from talent acquisition company saying offer is reflected is cognizant a professional company to behave like this ? I wasted one full day and waited for 1.5 months to say offer is rejected. I would say it as idiotic ### company.