No message left, although they triggered the voice mail recorder. When I tried to call back, I got the message that they "can't receive calls at this time."

Same here, call, no one there, a hang up, called back, got "cannot receive calls at this time." Wiki calls says it is registerd to MPOWER Communications. Probably phone solicititation.

no message.

I asked the caller to take me off their list and he said "Move to another house." I asked for the company number and complete name and he hung up. I called the number that appeared in my caller ID and it is a non-working number.

I suspect that these unsavory individuals call all the time, trying to sell condoms made out of sheep intestines.