This is typical of CO customer care's responses. They're there to disclaim liability, and in my experience, they're not interested in resolving a problem, rather they're interested in explaining why the problem you just experienced isn't really a problem. Precisely what they did in your case.

I would escalate this issue, and inform them that you intend to seek damages for them damaging your luggage (and related contents), and ask them to take your complaint seriously. If you get nowhere, file a DOT complaint and/or a small claim in your local court.