Number repeatedly appears on caller ID; I don't pick up s/he leaves no message.

annoying me

this guy calls all the time with a pre-recorded message
and wastes minutes on my cell phone.
I have called and requested nicely to remove my ph number.
The guy must me DUMB, then he changes his company
offer and continues to call back.
I really want the calls stopped.

Unsolicited caller left message: "Are you in debt?"