I got a call from this number, and since it was 8am on a frickin Saturday, and I was asleep, I didn't think too much of it; they had my exact balance, the checking account number that's attached to my credit card, etc... so I went ahead and made the payment. I got worried when I hung up, and called back the number. A lady picked up who authorized herself as being from Chase Bank only when I asked her.
So I immediately hung up and called the number on the back of my card. They couldn't verify the number, but they said that the payment amount that I had authorized had indeed been posted to my account and was processing; should be done in a couple of business days.
So it's not a scam number!
ALTHOUGH this might be relevent to people who have a Chase Card. They charge 15 bucks to process the payment over the phone, which the person had carefully neglected to tell me. When confronted (before the payment was authorized), he hesitantly told me about the 15 bucks, and when I said I was going to hang up and pay it online, he waived the fee for me.
Although this number has been verified by me and a couple of other people, my advice is to ALWAYS make your payments using the number on the back of your card; or online, or by check, etc. It's better than to put yourself through the uncertainity of finding out who called you, and if it was a genuine number. If you get your account up to date alternatively, they'll either stop calling you, or you can tell them that the payment's been taken care of.