Likely using some sort of demon dialer program that dials in numerical order. My cell is unlisted, kept very strictly private, and on the Do Not Call list but I still get scam calls. Scammers are going down a numerical list; i.e., 123-456-7890, 123-456-7891, and so on. It's that simple.
i got call on 11/15/10 at 8:29 pm. No one answer. no one called back yet but i will keep an eye. Someone has too much time on their hands to bother people i see.
I have asked these people many times to stop calling and I have also opted out of future calls with their own option at the end of each call and still they call. Even though they say they are a charity, I believe that they are just a scam trying to get money from people since they call non stop. I am also on the do not call list. They continue to call even on Saturday and Sunday mornings. I am sick to death of them and their annoying calls. Only a scam would pursue people like this, as a reputable charity would not harrass people on a daily basis.
I have been receiving calls from them.(616-608-1011) for weeks. Each time I call and press 1 for do not call. Then I get calls the next day. I talked to John at 1-734-246-9770 which is a satellite office of Insight Teleservices. He was putting out a notice. I'll see if this works.