These people are collection agencies. They are breaking the law by threatening you of court issues. They collect on old unpaid pay day loans. You can not go to jail for this. they way they are tiring to collect the past debt is illegal. Their number is probably ran through MajicJack and is why you can not find it in any listings. When you call in it says that the phone call is being recorded which is very very unlikely being that what they are doing is illegal, but with that because they are "recording" you do not need to tell them that you are recording so if you could find out who they are then you could take them to court but chances are you wont be able to find out who they are. Just tell them they have the wrong number and to have your number removed.