With all due respect, it kind of sounds like you put all of your eggs in one basket. Even if c9 wasn't bought, it's a bit short sighted to rely so heavily on a single service that has plenty of good alternatives.
Sorry about the lost videos, but that was a indeed a helpful comment. Any time you use any dependency, it's important to be aware of how it can change. Locking down a specific version, if possible, is generally a good route to take. Software in general, and especially SAAS, tends to change frequently, so building your project in an manner that safely handles changes is important.
The pitfalls of dependencies is something a lot of courses tend to ignore completely. Getting bit by dependency issues tends to be a hard-learned lesson, just like this one. Perhaps consider mentioning it in future classes.
