They've been calling my cellphone too, several times a week. Same thing, never leaving a message. I won't answer any number I don't recognize (because that marks my phone number as a viable one) so I have no idea who it is -- but I also don't give out my cell number very often, so it angers me that they've gotten their mitts on it somehow and are abusing it.
I am sorry I won't be able to help identify who it is, but I hope someone can find out.