Called me yesterday and they hung up when I answered on the 2nd ring. I tried calling back but it just stayed busy untill this evening, it just rings without an answering machine.

Calling my cell phone, don't leave a message.  "Rob" posted this in Feb:
"This is a company that validates phone numbers which are later sold to other marketing companies. Their job is simply to find out whether there is a live person on the other end and hopefully to verify the name. Once verified, they either mark the number as "live" or "dead". The live ones are passed on to clients who pay them money for this service. The dead ones are re-tried."
I suspect this is the case. Also these 'services' send out text messages hoping you will respond or "Stop". This will indicate the number is live...

Calling my cell phone, don't leave a message.  "Rob" posted this in Feb:
"This is a company that validates phone numbers which are later sold to other marketing companies. Their job is simply to find out whether there is a live person on the other end and hopefully to verify the name. Once verified, they either mark the number as "live" or "dead". The live ones are passed on to clients who pay them money for this service. The dead ones are re-tried."
I suspect this is the case. Also these 'services' send out text messages hoping you will respond or "Stop". This will indicate the number is live...

They cal me daily and have for over a month now. I try to call back and its always busy. Would love to be able to stop thiss. My caller ID says Citi when they call.