I just got the same thing on my cell phone. I called the number back and without identifying themselves it says "If you wish to be placed on our do not call list, press 1" So I did, they said another 24 hours to be removed. Still no idea who it is.
Call to my husband's cell phone from 'Jennifer' about installing security systems.
I added this phone number to 'Junk Call' on his phone's contact name list, so the next time we'll know not to answer. I put all the junk calls there, so the next time the caller ID will say 'Junk Call'.