Hello!
*Note* Criminals do not pay attention to Do Not Call Lists. They break rules, that's why they are criminals.
I am not a Microsoft Empolyee, but I can tell you that YES, this is a scam. I was called multiple times today. I finally stayed on and was actually connected to someone. He asked if I was the owner of 'the computer'. I have two, so I told him, "Yes, I do own my computers." and asked which one had a problem. (He can't tell me because there is no problem - IT'S A SCAM)
He asked if both were connected to the same internet. I told him (truthfully) that there are multiple computers connected to the same network here and again asked which one. He advised me that all computers would be having the same issue (even this would mean it's a network issue, not a computer one). I then asked why the caller ID showed it was my own phone calling. He told me it was because they were calling through the internet and so it was normal and not a problem.
I used to work in a legitimate call center and so I am familiar with at least a fewlaws about these things. I advised him that, in fact, it was not ok. In the United States, companies need to have the express consent of the owner of the cell phone in order to call it. Using a computer to make calls and playing a recorded messages are also highly regulated. I told him that they would actually need to have my express consent in order to legally contact me on my cell phone and not with a robo-caller. I said I would follow up with Microsoft on my own - and this is about when the call went dead.
Having worked in a law-abiding call center, I can tell you that Do Not Call registries and requests are taken VERY seriously as they get VERY expensive VERY quickly. If anyone ever questioned whether we were legit or a scam, we'd tell them we completely understood, gave them the company name and encouraged them to contact us back through a channel they trusted.
Unfortunately, as Microsoft are not the people doing this, they can do almost nothing to stop or prevent it. If you get a call from these people, PLEASE report it to the FTC. And hope for no more government shut-downs. The F in FTC stands for Federal so when the Federal Government shuts down, no one is or can work to stop these criminals.