I mix up CCC and NATO at times, so many new treaties got announced this past month, it can be a pain to keep track of after long protracted periods of nothing happening.
The rebuttal does work if referred to Non Grata at least.
It's generally called raiding, and if you haven't been successful for over 6 months, then there is something wrong with your business plan. You had at least one other nation, but even then you got rid of them (Pyro9K).
Get better war guides. Also, I wonder if CCC know you are attacking an alliance which they aren't presently at war with? @lilweirdwardthis guy is seriously your protectorate?