It was annoying me, so I sent them a message saying I had installed the antivirus (I hadn't, it's Windows only and I use OSX at work and Linux at home) and asked for my $25. They appeared a few days later in my bank account.
But the darn popup kept appearing every time. A month or two later, I messaged them again, saying I had installed the antivirus. A few days later, $25 in my bank account.
Oh well. If you pay me for your dumb popups, why not. I plan on messaging them again in a month or so :) (can't make it too obvious)