Firewall alert

i just had a popup that said "firewall Alert" and lists a website: firewallsecurityalert.com And a phone number: 1-870-505-4634 (toll free). It claims I may have adware/spyware and says I need to contact customer support. Is this legit? It doesn't look as if it is associated with apple. It won't let me use safari, and I have to finish some reasearch for a paper due tomorrow! Help!