This person called my company claiming to be "Tom Johnson" from Summit Manufacturing.  He was asking for information/names on people who work here.

Called claiming to be David Hayes, looking for people in our company using various excuses as "Someone called for support with a C# question", "Someone left a message looking wanting to grab a cup of coffee".

A client of mine called and an engineer here answered the call. Client stated that someone was calling them back because a "Joe" called them from that number last week.  The client assumed it was our engineer who is actually named Joe, so she gave them my number.  The person called stating he was "Dave Stevens" from "Summit Software" and said he was returning Joe's call.  I explained that Joe was on the phone, and asked if I could help.  He rudely asked who I was, so I again said my name, then he (again rudely) asked for my last name which I did not give, instead I asked what this pertains to, so he laughed and asked if my name was a secret.  So I muted him till he hung up.

Just got a call from Tony Lewis from "Summit Software." He said someone called about a .NET issue, but the name was garbled; he thought it was Matt. No Matt here. He was pushing hard for the contact info for the person in charge of our developers.

just got the same call here.  john harrison from summit.  calling for one of my engineers - this is obviously a recruiter.