I keep getting calls from this number and others with the 928 prefix.  Other sites report this as being in Gila Bend, AZ.  I've blocked the other calls but they just use a new number.  The don't give up, they don't leave a message and hang up before you can reach the phone.  I don't answer 'out of area', 'toll free', etc. but these folks are the real bottom feeders.