Interesting. I signed on to check responses and a few moments later the local ABC affiliate station began an investigative report about this very thing.
My general feelings were confirmed. It's a phishing scam. The Caller ID numbers are frequently spoofed. The "extended warranties", if they even exist, are hugely overpriced and cover little, but you won't know that until you pay and get the paperwork.
If you get calls like this contact the FTC and file a complaint.