Impostor- Microsoft scam

Had a close call last year with a man using the same tactic , wish I had kept the phone last year...I am always a skeptic, but I wanted to see what he had to say, I allowed him access again thinking he was Microsoft , but then he got to be sarcastic & that is what confirmed my thoughts & I just disconnected the DSL line without telling him and he couldn't finish what he was doing, I hung up on him, he called me back instantly, speaking very hatefully saying i wouldn't be able to access my computer &that they had control, but I new better & hung up on him again & grabbed my computer & went to best buy for them to look it over.... this time it was a lady describing the exact same words.."this is Microsoft & we have had alerts that someone is trying to hack into your computer.. I hung up on her this time & she keeps calling back