I wouldn't keep them on the line. they are not going to waste MY time which is way more important that whomever this scam person is. besides I heard if you keep a scam person on the phone, the more chances they can get control of your privacy.  trust me, don't answer; report on the do not call list. if they keep calling they will be charged a fee and you could also receive money if they keep calling you but you have to put the number on a do not call list first.