Cognizant Technology Solutions — HR not receiving calls neither responding to messages.

I had applied for Process Executive role (Voice) Mangalore location in your company. After a few days, I got a call from your HR( Name: Swathi, Ph No: [protected], Location: Andhra Pradesh, as per truecaller details). When I had got the call, I could not receive it due to my phone's issue. I tried calling to the number back once I saw the missed call in the log. But she was not responding to my call ( I tried calling many times continuously for 3 days) but my call was not answered. The number would be coming busy and also she declined my call on purpose. I also messaged her on WhatsApp and also put a sms but still the story is same.
A person always cannot answer a call due to personal reasons or technical reasons. But whenever a person tries calling you back or tries to connect with you multiple times for 3 continuous days and thrice by text, I can atleast expect a response right? Really disappointed by your HR as I was interested to take up the role. A candidate never ignores a call or declines a call from HR on purpose.