This some company calling itself "cardholder services" with a recorded message saying they want to lower my interest rates.  The girl who came on after the recording said it was for all visa and mastercards, and wanted my credit card numbers so she could "look them up".

Looks like a classic phishing scam trying to get valid credit card numbers from unsuspecting people.

I've never seen a valid number with a 000 prefix before - and a fake number showing on caller ID is very easy to do.