Malware on my iMac

Does not allow me to log off. Have to unplug. Says to update Flash Player-which I don’t use or call the number with a 623 or 632(Philippines) which I know is a scam. After unplugging for a longer time now seems gone. Installing an updated Malwarebyte program. Seems I’ve heard of this before. Help

Follow up. Malwarebytes 3 for Mac took less than 20 seconds to scan my HD and said I was clean. Seems awfully fast to check my HD. l heard about stuff like this, but its the first time it happened to me. I was on a R C Willey furniture store website looking at love seats and sofas when this happened. Any idea what I can do if this happens again? Is there any program out there I can use that will prevent this?
On the initial problem, I thought the area code was 623 (Arizona), but it probably was 632 (Philippines). After first unplug logged in with Firefox. No problem. Logged off. Restarted and automatically went to Safari and the problem page without hitting the Safari icon. Unplugged and waited about 4-5 minutes. Plugged in. Working normal.

For each browser that you use, install Ghostery and AdBlock Plus.

https://www.ghostery.com/
https://adblockplus.org/.

They will help keep out most of the bad things, but your diligence about what gets installed, or opened on your Mac will help keep your data safe.

I do have Ghostery installed and I see the bottom right rectangle on my screen that shows what's tracking me, but I don't know what i should do about it. Do I block any and all that is listed? Do I select individual ones or is it all or nothing? And how do I select individual ones? I guess what i'm asking is, what should my response be? If i block something is it blocked forever or only until I shut down my computer or go to another website? Pete

Go to the Ghostery preferences and set EVERYTHING to block. That's what i do. I you block it there, the bottom fight rectangle will show what's blocked.