I'm sorry that you had this experience with imgix. We have had challenges in correctly addressing support issues during this period -- support has been swamped. We've expanded that team, and we're continuing to do so.
You're right, we didn't tweet this blog post, but we did e-mail it to all customers with activity since Jan 1 2017.
In this case, we didn't properly convey that the Shopify integration guide we provided wasn't an official integration with Shopify. It was meant as a best effort "here's how you can do it" sort of thing. I requested that we take it down because it wasn't working due to a change on the Shopify side which prevented us from purging images.
I'd love to talk with you directly to try to make this right for you. If you'd like, my e-mail is in my profile.