I have an idea, it usually works for me on different products, it won't END the problem.
Every time that pop-up appears it might get re-activated (making the pop-up appear again) when you click on the option that lets you keep using your computer. The thing you should try is, let the pop-up show once, but don't click on it, just drag that window down to a corner where it doesn't disturb you, it won't appear again until you clicked on the option that allows you to continue using that free trial of their services.
I hope that you can still use the program with the pop-up activated.
All the best,
Tranc3r