I just bought a Hyundai and was told by the dealer to expect a call about th service I received. Probably the best way to handle it would be just to answer once and ask that they don't call back. Most reputable companies will accept that.
I have been getting calls from this number for about a week. I have never answered it but they keep calling and never leave a message. I am just hopping they go away. My caller ID just says CA which I think that means California.