They can't legally enforce a 6 year old debt in California. The legal time limit is 4 years. Hang up on them. If they write to you write them, certified mail return receipt requested, requesting validation of the debt under the Fair Debt Collection Practices Act. If they sue you, write me.

Mr. Stone gave you what would have been a good answer, if the debt were governed by California law. Unfortunately, if you have a contractual debt incurred in another place, California's statue of limitations does not apply. Unless he is a master of International Law, which based on his history of answers he is not, you also cannot trust his assumption that the Fair Debt Collection Practices Act applies (though it may). As for your direct question, Californa has jurisdiction over anyone who is present in the state. Where the debt arose is irrelvant to jurisdiction. I agree, however, that you should send a letter demanding validation of the debt. You might see if anyone back in New Zealand can find an attorney who can tell you what the statute of limitations is back there. If they cannot prove up the debt, and/or the Kiwi limitations period is less than six years, refuse to pay. You can contact Mr. Stone at that point if you like, although based on your zip code I am probably more convenient and would be willing to discuss the case with you as well.

I'll throw in my two bits: You need to refer to your original credit card agreement. Since this agreement is a contract between you and the credit card issuer, you may have agreed, i.e., contracted, to waive any statutory limitation, regardless of whether we are talking about California or New Zealand. (Though I doubt this is likely to be the case.) Furthermore, you may have contracted to submit to the law and venue of other jurisdictions--possibly (though unlikely) even California. The California collections lawyer is governed by State and Federal law, as well as State Bar rules of professional conduct. Don't be bullied, and good luck.