Just got this call, too, but was surprised to see that the number only had two other reports here. Nobody was on the line when I answered, suggesting illegal robocall. I'll be promptly reporting to the FTC Do-Not-Call complaint line.
I get 1 call a day and when I answer there is no one there. One time I answered, muted my phone and left the line open for an hour to run up their phone bill. Its the least I could do. The calls have not stopped.