Hi everyone,
The issue was caused by your account being in a pending state, while awaiting credit card verification. This is usually close to instant, but sometimes there are delays. While in this state, your project is *not* activated for billing. I realize that this isn't clear (where it says "billing enabled"), and we'll work on improving the messaging.
Independently, you hit upon the fact that the traffic stats page includes failed requests. This is a known issue and one we're working to fix - initially, we actually thought it was a feature, but realized that it would be confusing and I hope that we're soon able to show both failed and successful requests independently.
I also want to make perfectly clear, that you're not charged for failed requests.
Thanks for pointing this out and sorry for the inconvenience.
Cheers,
Adam