epcassist.com locked up my browser to sell virus protection Internet

this internet scam company told me I had a virus on my computer with a pop up window that locked up my browser in order to sell me virus protection to unlock my browser , I had someone look at my computer and nothing is wrong with it. Except a locked up browser with there warning on it. I used a different browser and the computer works fine. I spoke to them an the phone and they wanted 249.00 dollars to unlock my browser (safari). But they tell you your computer is infected with a virus or may be infected with a virus. All they do is lock up your browser take your money and unlock your browser.