He said; she said. A Layer 7 attack is not necessarily something one might "notice." The very nature of such an attack is "normal" looking. I think it's impossible for us to say who is right -- OP or CloudFlare -- without substantial hard-data. Ultimately, it's not the basis of the article, and the OP is looking for a different service -- unmanaged, limited-downlink bandwidth -- than what CloudFlare is looking to provide -- managed, edge network.
Irregardless if it's an attack or not, CloudFlare's personell did not handle this well.
Yes, I know they did offer one hell of a starter/"sweet lolipop to sucker you in" pack - but that's still not what's being discussed.
It has been re-iterated many times in this thread - but CloudFlare had a sane person on the other end that was willing to open his wallet - that's something one should act on quickly.
