Can't figure out who this number is coming from.  Help

I get this number (310)601-1190 showing up on my home caller ID as unavailable.  When I call that number right back it says the number has been disconnected.  How can a number be disconnected 30 seconds after it just called me.

I have got several calls from these people. The person on the other end speaks very broken English with a very heavy Spanish accent. I told the guy we are in the U.S. and he should learn to speak English then I hung up. Very fishy! I have told them stop calling, but they continue. It is very fishy. Sounds like a fraud/scam. The Caller Id reads "Unavailable". I have never seen such a thing!

I believe this comes up when someone is using certain type of calling card.

This number 1-310-601-1190 has been on my caller id several times a week but no one ever leaves a message. Im not home to answer when they call and would probably not anyways because no caller id is issued.