I received a call from 646-779-7157 on Tuesday morning closed to noon. The caller ID didn't show any info other than their number. I don't recognized the number and it's the same area code in my city, New York City. From my experience, I believed that is a soliciting phone call with a system that can generate a temporary caller ID from the same city where you lived.
I than called that number back to see who they are. But I have to hide my number to appear in their caller ID in case they still wanted to test if my number is a legitimate number so that they will try again in the future. I then dialed *67 (that can hide my number) before dialing -646-779-7157. It rings once and a robot answered with a message: "Thanks for calling. The survey that you were called for has now finished. If you would like to be removed from our list for future calls, please press nine."
Now I know this is an illegal call from a marketing company. I didn't press nine and I advised everyone not to do so because that would allow them to confirm your number is a good number. Since I have registered to the federal government's "DO NOT CALL REGISTRY" I am going to file a complaint online.
Here is the website to report unwanted calls: https://complaints.donotcall.gov/complaint/complaintcheck.aspx
National Do not call Registry: https://www.donotcall.gov/default.aspx