Cognizant — got early engagement but no offer letter

Address: 462023

Website: www.cognizant.com

I had attended a drive on 21st july 2018. I had been told to wait for three weeks for my offer letter. I mailed them and got a reply saying that my offer letter is already released. But i see no mails in my inbox and spam box. But two days back i see that i have got an early engagement mail. I have been trying to get in touch with the hr but she won’t reply now where in her last mail she said ‘contact me if you don’t get it in two days’. It’s been more than a week now. Am i supposed to look for a new job than wait for a whole year like this and see my batchmates get the joining before me?