I'm not doubting your site was "down for four months". I'm doubting the part where you said "They just shut down the Python app engine sites with no notice".
Most notably, I know many people who run these types of sites and outside of GAE being mediocre, I've never heard them complain about anything like that.
This was the very first version of app engine that rolled out in 2008 or so. It showed some type of "incompatible version" notice in the admin ui when I noticed it, and when I tried to redeploy the sites using the command line deploy tool. I switched everything to s3.
Most notably, I know many people who run these types of sites and outside of GAE being mediocre, I've never heard them complain about anything like that.