If you, like me, don't like receiving telemarketing calls and live in the U.S., the federal government maintains a "National Do Not Call Registry" that telemarketers are supposed to refer to before calling phone numbers. If a telephone number is on the list, the telemarketer is not supposed to call the number. You can add your phone number to the list by pointing your web browser to the National Do Not Call Registry website.
Unfortunately, some telemarketers ignore the list. If they do, you can file a complaint at the complaints page. You will be asked to provide the number that was called, the approximate time of the call, and the calling number, which you may be able to get by Caller ID or by hitting *69 on your phone immediately after the call has ended to get the time of the last incoming call. You will also be asked to provide the name of the company, if you know it.
I received an automated call today telling me I hadn't responded to prior offers to reduce my credit card rate and this would be my last chance. I hit "1" on the phone to speak to someone. When I asked for the name of the company I was told it was "Branch Card Services", which is probably not the real name of the company for which the telemarketer or scam artist I spoke to works. When I asked where the company was located, he immediately hung up. I hit *69 on my phone and found the number from which he was calling was 971-220-1771. I then went to the National Do Not Call Registry website and filed a complaint, since my phone numbers have been on that list for years. A company that ignores the list is subject to being fined by the government for ignoring the "do not call" list.
When I looked up the number on the Intelius reverse phone number lookup site, I found the location for 971-220-1771 listed as Gresham, Oregon. Of course, such companies can employ Caller ID spoofing techniques to hide the true number from which they are calling, so the number you obtain from Caller ID or *69 isn't guaranteed to be the number from which the call was placed.
You might wonder who would be foolish enough to provide a credit card to someone who calls when you have no means of verifying the caller's identity and no way of knowing if he isn't just a scam artist collecting credit card numbers to sell to others or use himself. Obviously, such calls must work, though, since I often receive them. I can usually get the person on the other end of the line to give me a company name, all of which have sounded rather dubious. Sometimes, I can even get the person to give me the location from which he or she is calling. In one instance, when I told the person that I shouldn't be getting such calls because I'm on the "do not call" list, she asked me how she could get on the list; I told her to go to donotcall.gov.