The same has happened to my parents 2 times. They have hung both times and feel like this is a scam as referred to below.
I got a call today 12/22/08 and no answer. i tried to call back and just goes to a voicemail with the number stated only.
This is at least the 2nd time this number has called. The entire message is an interactive recording. They claim to be from some credit card company I never heard of and say they are showing "suspicious activity on your account today." They then proceed to ask you to enter your credit card # on the keypad. They said they would ask for 3 pieces of information but I hung up at this point. Sounds like a pfishing expedition to me.