I'd just ignore it out of principle. They won't have a CC on file and I never agreed to these terms. Good luck collecting since what they're doing isn't legal in pretty much any jurisdiction, and I reject the idea that I need to take action to not be billed.
It may or may not be defensible but chances are the terms of service you agreed to included a phrase that states they can make changes to those terms and you have to review them periodically or you’ll be deemed to have accepted them.
Luckily we live in "law is law" land and not "contract is law" land, and the law does take kindly to concepts like hotswapping concepts in a predatory manor.
