Got the first call from these guys today.  They didn't leave a message, I was hoping that someone could tell me who it was, however, I am the first to inquire about this number

A machine like male sound said: "I'm Michael, you may pay high interest rate on your credit card ...", I hanged up.

I called back immediately, a pre-recorded female sound said: "The number is removed from system ", then a beep.

We get daily calls from this number.  It's almost harassment call.  Having call display helps to see who call and we usually don't answer and end the call. I found out today that by dialing *60 it blocks your telephone # for future calls.  I'll try it the next time it occurs, any calls that could be a telemarketer.