iYogi is a real company, but they have a poor review:
http://www.pcmag.com/article2/0,2817,2456682,00.asp
However, I really doubt your caller was the genuine iYogi company. Most of those "your computer is infected and we can fix it" calls are from overseas, and the scammer spoofs the phone number you see on your Caller ID. The scammer also pretends to be a real computer associated company... frequently stating they are "Microsoft" or "Microsoft associates".
Bottom line:
If somebody calls you to tell you that your computer needs fixing,
Hang up immediately - it is a scammer.
Yeah, I got a call from this number this morning. He kept telling me I was going to lose my computer and my software was going to be blocked. I told him he was a liar and he could stick his scam. He got his "lead engineer" on the phone to pressure me. I explained he was ridiculous because I use a MAC...The guy screamed at me saying "You are a stupid talker, I hate stupid talkers you don't deserve to use your machine. It ok for Windows to take it away from you" then he hung up on me....IDIOTS!!!!