who is calling me at this number and for what

I got a call from this number this morning on my business line, and when I answered there was nobody there and the call immediately hung up on me....
So, I called back the number from my personal line, and was instructed that the caller was on another line, and asked to leave a message, which I did??
I do not recognize this number, am on the do-not-call list, and so I do not believe this is some form of spam advertising, but it could be. I am completely in the dark here, and am hoping that anyone can tell me what this call is regarding!!

Hey, you want to know who's calling? Answer the F***king phone moron!!!!  If it's a unsolicited sales call, then ask to be taken off of their list. pretty simple

This is a call from "Nitro Digital Marketing" trying to find out information about your personal (or business) website. He's trying to get information from you and claiming to be connected somehow to Google. Strange thing was that he knew my first name. Be wary of people calling out of the blue trying to "help" you and get information from you.

Why are people like you allowed to keep breathing?