This is a scam. They are pretending to be a tech support service and are trying to gain remote access to your system.
I nearly fell for this a few years ago because I did have a remote tech service that I subscribed to and I thought it was them. I got suspicious with some of the information they were asking for and luckily I hung up and contacted my tech support company who tried to locate them. Unfortunately, because they switch numbers, they couldn't be found.