Qualcomm HR not responding after giving a verbal offer

I recently interviewed for Qualcomm Bangalore for the Autonomous Driving team. After completing interview loops from India and San Diego, I had a Director round and was given an assignment to complete which I completed the next day(working all night) as Director said that he would be waiting for my assignment. After 1 day HR asked for my salary details and shared a verbal offer to me. He told me that it would take a week to release the offer letter. In the meantime, I had asked the HR to send me a salary breakup over email. 1 week has already passed. I tried emailing/calling the HR but he is not picking up my phone or responding to my emails. What should I do? #qualcomm #bangalore