Ellen feels like she got ripped off by Microsoft. She got a popup saying she had a virus and listened to it, then paid $250 for support. Leo says that wasn't microsoft. That was a bad guy. Leo says it was a browser popup and they use that to phish for gullible people to sign up. Microsoft will never, ever do that. It's even worse, though. They likely got remote access and not only do they have her credit card, they have also likely installed more malware on the computer. At this point, Ellen should call the credit card company, reverse the charge and have her card number changed. Then she can backup her data, format the hard drive and reinstall windows.
The FTC has a good technote on how you can get your money back after a tech support scam.