These are help desk people for corporations. I just ignored the call and they called on my office phone after I had placed a call to them. Same number - they just rang my cell phone first so I didn't answer because I didn't recognize the number.
This is the number for the Accenture Help Desk for outsourced services. The number comes through without a caller ID, so most of the time I ignore it. Very rarely will they leave a voicemail; sometimes I answer and there's no one on the other end. Although the area code says California, it's coming from India.
In my case, the calls are legitimate, as I'm doing business with the company that they are being paid to support (their ability to provide effective support is dubious, based upon my experience with them). However, the lack of a caller ID, failure to leave voicemails, and failure to respond when I do answer the phone speaks to a culture of poor (or badly trained) phone etiquette.
My mother answer a call from this number. Lady was looking for me yet does not want to introduce herself. My mother got upset and thought I am mixed up with something bad.
Received a notice of a call from this number on Google Voice Mail but without any message. I think this is the second or third call from this number. If someone doesn't leave a message I just delete the notice of the call. A bit of a waste of time.