I'm in the same boat. And if you contact support to find out how to remove the annoying popup ad, as directed, they will simply send you instructions on how to uninstall CCleaner and download/install the free version.
This was definitely either a bait-and-switch or a campaign to hide the fact that these licenses were only good for a year. I will set up a google alert to notify me of when a class action lawsuit is filed against Avast/Piriform.