mal or virus or what?

Got a strange prompting from my iMac informing me that my "Network security is at RiskContact Technical Support"  Contact Apple Certified Technician at (844)325-1334.  Couldn't clear my screen so I called the number which sent me to 5 seconds of elevator music and then a foreign voice picked up and introduced themselves.  I hung up and immediately was called by a number (877-821-4559).  Didn't answer and they called again.  I answered and could tell it was the same person.  I told him I did not need any solicitations and he began cursing me out.  Ha!  Getting cursed out by a 3rd world country scammer.  Just putting this out there if anyone would like to comment.  I did get a message prompt on my iMac also that stated that "An unknown service (port 8770) is starting on your Mac.  If I don't change my firewall settings, the firewall will block connections from other computers to this service on your Mac."  Is this something that I should be concerned about?