It's not Microsoft, be smarter than this. This is a very old scam that has been addressed on several occasions throughout the years. Microsoft has published articles about this reporting their tech support numbers so that people don't get confused.
I got a call from this number just a little bit ago. I was driving and accidentally answered hit the answer button instead of decline. Since I answered I thought it would be rude not to speak to a likely telemarketer.
The first Indian guy told me that they were getting several error messages from my Windows computer and that he'd like to help. I work in the IT industry and knew immediately that this was a scam. I also own 4 Windows PCs so I asked him to identity the PC with errors. He struggled give me an answer and then told me we could fix the problem from any PC. That would be a neat trick if true, but another clear sign it's a scam.
When I asked if he was with Microsoft he wouldn't use that company name. Just Windowns tech support. I then asked for his manager. After a minute on hold the manager with a slightly easier to understand accent seemed annoyed that I demanded verification. He would not name the company he works for. He asked me to stop lying, then started talking about God. That's when I told him that he was speaking to an atheist and the God card wouldn't get him very far. Then he said he'd call back on Monday and I told him to delete my number.
This is 100% a scam. Feel free to [***] with these guys if they call. Microsoft tech support is not free and it's not proactive.