CACH, LLC Default Filing for CA Received

:?: Im so confused, and I am hoping that some of you can help (although I am also in the process of obtaining legal assistance).

I live in California, and had a credit card debt, owned by Providian, who then merged with Wamu I guess shortly before I couldn't make payments anymore. Long story short, to get a divorce from an abusive spouse, I was stupid and agreed to take on a large credit card debt (that was just in my name because his credit was bad). It was about $8k at that time.

Well, I didn't realize that I couldn't afford the payments, and live on my own. So I stopped paying the credit card payments around spring of 2006. I got a lot of collector calls, and the debt moved around from collector to collector. I tried to work with a few to make a settlement, but they were all sleazy, and wouldn't agree to pursue matters further even if I made an agreed upon payment amount. So I began writing Cease and Desist letters (?sp) everytime collectors changed hands. Until...CACH,LLC. They have been calling like crazy, and ignoring do not call letters.

Sorry for the long post, but I have so many questions surrounding the following situation:
I just recieved a notice from CACH LLC via regular mail (it wasn't even certified mail). Inside, was a copy of a filing for default judgement with the Superior Court of CA. It wasn't signed or stamped by the courts. And the judgement amount entered was $0.00.

So I am totally confused. I haven't received a summons at all for a court date, and my limited knowledge of law (coming from my divorce), is that a Default filing is made when the defendent doesn't respond to a summons or court hearing. So is this default filing valid? What do i do with it? Do I respond some how, and to who? I have no way to pay this debt, and no assets other than a 401k, so do I need to file for bankruptcy to stop this?