Let me tell you all this. I have Verizon. I found an $11.00 charge on my bill for a call to Canada from one of my lines that has international called block. So how did the call get on one of my verizon wireless lines if the line is NOT allowed to call international? Who has been hacked?
I tried everything above, nothing worked. Finally just hit command-w over&over&over as fast as I could while clicking "ok" and "leave page". Eventually got the command in and the tab closed.
My wife called me to say we got the pop-up message on Safari. I called the number from a benign phone number and spoke with them, they could not give me a company name they were working for. They said they were Apple technicians. I said, "I figured this was a scam." The guy hung up on me.
I called the number. He wanted to access my computer. Told him no way. Googled the number and seen these posts and shut everything down. Now I'm worried they have my phone number.