I don't know the details of this, but I'm guessing other than suing Google or managing to create a popular thread on Reddit or HN that causes an extreme problem

I don't know the details of this, but I'm guessing other than suing Google or managing to create a popular thread on Reddit or HN that causes an extreme problem for them, you're probably shit out of luck. They've already refunded the time frame that might have been chargeback-able. Even if you could chargeback further back than that, you risk retaliation to your Google accounts if you proceed with that. The best thing for you in the long-run is to transition away from Google's services. Their lack of support for most people makes them too much of a risk to run your life with them.