1. If you wanted Retool to stop using your service, you should have said it up front instead of beating around the bush. From what I can gather from your emails, you sent their CEO a random sales pitch and he ignored it. Hard to fault him for that.
2. I love faker.js. I have used it in the past, and I'm sure several teams in my company use it today. I would, however, never ever pay for your cloud service, simply because taking a dependency on a third party hosted website to run unit tests is madness. The old school corporate software licensing model might be losing favor, but that does not mean it isn't apt for any use case. If faker.js was still downloadable but needed a license key to run I'm sure people would pay for it. It would probably be the easiest thing in the world to bypass, but the same Fortune 500 companies you mention would gladly break our their checkbooks rather than risk getting sued.